This makes me LOL a bit. The car alarms in South America are asinine. Ubiquitous, one might say. It reminds me of when car alarms first became common in the US back in the 80's. They would sound off all the time. I think it's an attempt to say, "Hey, look at me. I own a car!" more than any thwart against theft. Normally, if you'll actually look at the alarm going off, the owner is actually there acting like it's a mistake that he tried to get into his car, yet the alarm just decided to "accidentally" go off. It's a big deal to own a car in South America. They're very proud of their cars. Many Ecuadorans and Colombians told me it was a big deal to own your own vehicle. Even a little beater is considered by many to be an object of pride. I can't blame them for that.
I was in a hotel in Quito for a couple of weeks where a car parked on the street would sound off every time a garbage truck or bus would pass by. It was right outside my window. It was ridiculous and annoying, but I still thought it a bit funny. They just like their cars. I think they set their alarms so sensitive so that everyone will look. But we've all heard of the "Boy who cried wolf" right? If they're always sounding off, then if a guy were actually stealing a car, who would ever think he was anything but the owner? All a car thief would have to do if anyone actually looked would be to just smile and wave and act as if it were an accident.
One thing I did notice... After I had been in South America for almost 6 months, a Gringo expat asked me, "When is the last time you heard a siren?" I had to think about it a bit. And then I said, "Shoot, I know I've heard a few short bursts of police sirens at intersections and such, but besides that, I can't remember during this six months ever hearing many sirens at all." I get back to the USA and stay in a hotel in Louisiana, and I hear sirens literally every hour coming through the intersection right outside my room. And not just a siren, they're blowing air horns and all that annoying crap. It seems to me that there are more fires and crimes and dire emergencies in the US than down South.
But yeah, the alarms and the roosters in South America can get annoying.