The hard part of the whole operation is getting the damn alarm turned off. If it's a commercial alarm company, they probably have an override code you can punch in. If it's a Radio Shack, home install, you just have to find the siren and cut the wires to stop it. By that time, you've got every kid, old lady and busy-body in the neighborhood standing on the front lawn.
Couple of funny stories:
1) A few years ago, friend of mine who lived in Detroit went off on vacation and asked me to check in on her pets. She gave me an access code to her alarm, the "it's really okay" password and a key. No worries, I thought.
So I show up the first day, unlock the door and I've got 30 seconds to key in the code. I do. But the code's not accepted. I try again. The code's not accepted. I try twice more and the code's not accepted. The alarm goes off, blaring throughout the house and the neighborhood (and it was a decent neighborhood, mind you) and scares the animals, except the dog (who desperately needs to do his business). I go wait by the phone for the alarm company to call and they don't.
After five minutes, the dog's going insane with his need, so I take him out (no fenced in yard, he has to be on a leash) and deal with him and all the feeding/watering/litterboxing/etc for about 25 minutes. All the time the alarm is screaming insanely into the early evening air.
I stick around for another 10 minutes, hoping that someone--anyone--will call, show up, whatever and shut this thing off. Mind you--in all that time, NOT ONE neighbor has peeked their head out the door, window, did more than glance over as they got in/out of their cars, nothing.
Finally, another friend of the friend drives up and says the alarm company called HIM to find out what's going on, and he called them on his cell phone, gave them the code and everything finally got shut off.
Seems my friend didn't register the code she'd given me with the alarm company after all, so he gave me his code and we were good for the rest of the week.
2) My ex-m-i-l had an alarm on her house with a nice fob. One day, she slipped in the snow coming in from her car and broke her leg. She got the fob, set off the house alarm so it blared. Again, not a single neighbor looked out to see her collapsed on the front walk. She laid in the snow for the 40 minutes it took for the cops to get there.
Those experiences pretty much has killed my expectations of neighbors (or even cops) caring a whit about a house alarm.