I just experienced this silliness, my sims are living on Cay to the City, it's a fair distance from the main islands one of them is in law enforcement and actually self teleports to the carpool in the mornings then takes hours to boat home at night.
Well the alarm went off waking both sims and they go down to deal with the burglar, one being a police officer the other brave, then all three just stand about for what seems like hours waiting for the cop to show up in his speedboat.
He finally arrives and goes and stands directly behind the burglar for about an hour then bleats he can't get to him
so he then decides to go swim in the pool instead while my police woman deals with the burglar followed by her husband just to be sure.
The cop then arrests the burglar and they go off and my sims go back to bed, quite a while later I go to save my game and it tells me I'm being burgled, but that was hours ago
Sure enough the cop has left the burglar outside the Alto's house and is heading back to check my home over, so in all it's taken almost half a day to deal with one burglar that my sims were quite capable of doing on their own
I shall be selling the alarm now rather than do this again.