You'd have to prove the intent to charge the caller with mischief, unless there was a pattern of fake calls that'd be tough to do.
Can't say about fire alarms but I know out in Vancouver if you have too many false alarms with your entry system you'll loose your permit and be fined.
Right now out West they're executing tons of warrants looking for grow ops in folk's houses. Along with the Police there are city bylaw folks. They gain entry, see there's no operation in the place but instead of leaving they proceed to search for building code infractions and if they find any they slap a vacate order on the place. That seems more draconian to me than this incident.
Airsoft, where nothing is hurt but feelings.