Wonder if it is possible to ‘permanently’ change the answer to ‘add to calendar’ to ‘check, added to calendar’. I know it makes that statement when you add to calendar (I caught it flash by while adding a reservation) but it changed back almost immediately to ‘add to calendar’ which may lead a person (ME) to add it multiple times.
After tapping Add to Calendar, the button now says Added to Calendar with a checkmark, so it’s quite clear. This will be synced across all devices. The button still works, so tapping it again will add it to the calendar again, which could be useful.