diff --git a/docs/config-template.yaml b/docs/config-template.yaml
index 9e91429..5a6969d 100644
--- a/docs/config-template.yaml
+++ b/docs/config-template.yaml
@@ -143,19 +143,23 @@ choices:
         - regdesk
     early:
       description: 'Early Bird Discount'
-      price: -500
+      price: -1500
       vat_percent: 19
       visible_for:
         - regdesk
       default: true
       read_only: true
-    door:
-      description: 'At The Door Fee'
-      price: 1000
+      constraint: '!day-wed,!day-thu,!day-fri,!day-sat'
+      constraint_msg: 'Early Bird Discount does not apply to Day Tickets'
+    late:
+      description: 'Late Fee'
+      price: 1500
       vat_percent: 19
       visible_for:
         - regdesk
       read_only: true
+      constraint: '!day-wed,!day-thu,!day-fri,!day-sat'
+      constraint_msg: 'Late Fee does not apply to Day Tickets'
     stage:
       description: 'Entrance Fee (Stage Ticket)'
       price: 500
diff --git a/internal/service/attendeesrv/attendeesrv.go b/internal/service/attendeesrv/attendeesrv.go
index 758bc12..3c4e28d 100644
--- a/internal/service/attendeesrv/attendeesrv.go
+++ b/internal/service/attendeesrv/attendeesrv.go
@@ -217,8 +217,16 @@ func userAlreadyHasAnotherRegistration(ctx context.Context, identity string, exp
 }
 
 func checkNoForbiddenChanges(ctx context.Context, what string, key string, choiceConfig config.ChoiceConfig, originalChoices map[string]bool, newChoices map[string]bool) error {
-	if choiceConfig.AdminOnly || choiceConfig.ReadOnly {
-		if originalChoices[key] != newChoices[key] {
+	if originalChoices[key] != newChoices[key] {
+		// tolerate removing a read-only choice that has a constraint that forbids it anyway
+		if choiceConfig.ReadOnly {
+			if originalChoices[key] && !newChoices[key] {
+				if canAllowRemovalDueToConstraint(ctx, what, key, choiceConfig, originalChoices, newChoices) {
+					return nil
+				}
+			}
+		}
+		if choiceConfig.AdminOnly || choiceConfig.ReadOnly {
 			if !ctxvalues.HasApiToken(ctx) && !ctxvalues.IsAuthorizedAsGroup(ctx, config.OidcAdminGroup()) {
 				return fmt.Errorf("forbidden select or deselect of %s %s - only an admin can do that", what, key)
 			}
@@ -227,6 +235,23 @@ func checkNoForbiddenChanges(ctx context.Context, what string, key string, choic
 	return nil
 }
 
+func canAllowRemovalDueToConstraint(ctx context.Context, what string, key string, choiceConfig config.ChoiceConfig, originalChoices map[string]bool, newChoices map[string]bool) bool {
+	if choiceConfig.Constraint != "" {
+		constraints := strings.Split(choiceConfig.Constraint, ",")
+		for _, cn := range constraints {
+			constraintK := cn
+			if strings.HasPrefix(cn, "!") {
+				constraintK = strings.TrimPrefix(cn, "!")
+				if newChoices[constraintK] {
+					aulogging.Logger.Ctx(ctx).Info().Printf("can allow removal of read only %s %s - it would violate a constraint for %s anyway", what, key, constraintK)
+					return true
+				}
+			}
+		}
+	}
+	return false
+}
+
 func checkNoForbiddenChangesAfterPayment(ctx context.Context, what string, key string, choiceConfig config.ChoiceConfig, configuration map[string]config.ChoiceConfig, originalChoices map[string]bool, newChoices map[string]bool, currentStatus status.Status) error {
 	if ctxvalues.HasApiToken(ctx) || ctxvalues.IsAuthorizedAsGroup(ctx, config.OidcAdminGroup()) {
 		return nil
diff --git a/test/acceptance/attendee_acc_test.go b/test/acceptance/attendee_acc_test.go
index 9436334..3e5a1d7 100644
--- a/test/acceptance/attendee_acc_test.go
+++ b/test/acceptance/attendee_acc_test.go
@@ -763,6 +763,43 @@ func TestCreateNewAttendee_AutomaticGroupFlag_CannotSet(t *testing.T) {
 	})
 }
 
+func TestCreateNewAttendee_ReadonlyDefaultPackageWithConstraintRemovable(t *testing.T) {
+	docs.Given("given the configuration for login-only registration after normal reg is open")
+	tstSetup(true, false, true)
+	defer tstShutdown()
+
+	docs.Given("given a logged in user")
+	token := tstValidUserToken(t, 101)
+
+	docs.When("when they create a new attendee and remove a read-only default package with matching constraint (stage)")
+	attendeeSent := tstBuildValidAttendee("na63-")
+	attendeeSent.Packages = "room-none,day-sat,boat-trip"
+	response := tstPerformPost("/api/rest/v1/attendees", tstRenderJson(attendeeSent), token)
+
+	docs.Then("then the attendee is successfully created")
+	require.Equal(t, http.StatusCreated, response.status, "unexpected http response status")
+	require.Regexp(t, "^\\/api\\/rest\\/v1\\/attendees\\/[1-9][0-9]*$", response.location, "invalid location header in response")
+}
+
+func TestCreateNewAttendee_ReadonlyDefaultPackageNoConstraintNotRemovable(t *testing.T) {
+	docs.Given("given the configuration for login-only registration after normal reg is open")
+	tstSetup(true, false, true)
+	defer tstShutdown()
+
+	docs.Given("given a logged in user")
+	token := tstValidUserToken(t, 101)
+
+	docs.When("when they create a new attendee and try to remove a read-only default package with no matching constraint (room-none)")
+	attendeeSent := tstBuildValidAttendee("na65-")
+	attendeeSent.Packages = "day-sat"
+	response := tstPerformPost("/api/rest/v1/attendees", tstRenderJson(attendeeSent), token)
+
+	docs.Then("then the attempt is rejected as invalid (400) with an appropriate error response")
+	tstRequireErrorResponse(t, response, http.StatusBadRequest, "attendee.data.invalid", url.Values{
+		"packages": []string{"forbidden select or deselect of package room-none - only an admin can do that"},
+	})
+}
+
 // --- update attendee ---
 
 func TestUpdateExistingAttendee_Self(t *testing.T) {
diff --git a/test/testconfig-base.yaml b/test/testconfig-base.yaml
index d6129c7..ccf0992 100644
--- a/test/testconfig-base.yaml
+++ b/test/testconfig-base.yaml
@@ -140,13 +140,12 @@ choices:
       constraint: '!attendance,!stage'
       constraint_msg: 'Must disable Convention Ticket and Stage Ticket for Day Guests.'
     day-sat:
-      description: 'Day Guest (Saturday)'
+      description: 'Day Guest (Saturday) Self Booking Allowed due to constraints'
       price: 6000
       vat_percent: 19
-      read_only: true
       at-least-one-mandatory: true
-      constraint: '!attendance,!stage'
-      constraint_msg: 'Must disable Convention Ticket and Stage Ticket for Day Guests.'
+      constraint: '!stage,!attendance'
+      constraint_msg: 'Must disable Stage Ticket for Saturday Day Guests.'
   options:
     art:
       description: 'Artist'