diff --git a/src/pretix/static/seating/seating-plan.schema.json b/src/pretix/static/seating/seating-plan.schema.json
index 20ef84a08e..4ecabd1ea3 100644
--- a/src/pretix/static/seating/seating-plan.schema.json
+++ b/src/pretix/static/seating/seating-plan.schema.json
@@ -106,6 +106,7 @@
       "properties": {
         "seat_guid": {
           "type": "string",
+          "pattern": "^[^ ].*[^ ]$",
           "description": "Seat global ID by which it can be identified. It should be globally unique (not just per row). It doesn't have to be pretty since it won't be shown to the user."
         },
         "seat_number": {