The only difficult ones are where reasonable people can disagree on whether it is a "vehicle". Like the rowing boat or the bicycle, or whether "wagon" refers to a little platform or a lorry.

Otherwise it comes down to "is it a vehicle?" and "is it in the park?". There are comments from people saying they said that a police car or ambulance was not a vehicle in the park because it had a good reason to be there, which to me makes no sense at all.

The game makes very clear that it is not "would you allow this vehicle in the park?" but "is this a vehicle in the park?".