? for goalposts

The revolving door at my workplace in Oslo. The exclamation mark I understand: it means "attention!", which is fair enough - you wouldn't want to mistake a revolving door for a normal one. Who knows where that could lead? The "lead children by the hand" one seems fairly sensible as well. But who on earth would attempt to play football in a revolving door? Unless that is how Johan Cruyff perfected his famous turn. Still, the sign seems to be effective - in about 15 months since the building opened, I have yet to see anyone attempting to play football in said revolving door.