Friend's daughter's 05 Neon. Alarm goes off randomly when activated. Doesn't go over well in thier neighborhood. I think it goes on and off over the period of the night.

Any clues what might cause this?

My '01 Neon did that right after I bought it new. I was living at the back of an apartment building and couldn't hear it going off until I got up on a Saturday morning. Bad rain storm made it go off and apparently it had been going off, off and on all night. My neighbors weren't happy, LOL. Anyway, I had to take it to the dealer to have them adjust the sensitivity or something.

My 02 Neon occasionally did it - more in hot weather.
(While it was under warranty the dealer had several attempts to fix it - never did...)
From memory, I think the problem is that the sensor (in the roof lamp housing) was way too sensitive. There is an adjustment under the housing cover, but that didn't fix anything...)
According to the manual, if you lock the car with the remote three times, it disables the interior alarm - did that ever work? You guessed it...