I also had a bad experience with HotWire, with the alarm on my previous car. Firstly, they couldn't get the alarm hooked up correctly to the central locking. It would just lock and unlock. One of the alarm fobs stopped working (the light remained on and I replaced the battery and re-programmed both fobs to be sure, and that one still wouldn't work).
I have sold the car a few months ago, so I'm not really that worried anymore, but since you brought up the topic, thought I'd add my 2 cents.
It's also turned me off alarms, I would never have an alarm installed in a car again.