Cheech

No security system, just a homegrown light kit. Here's a list from a guy I know on another forum:

1. Xena Disk Alarm Lock (or knockoff). This rotor lock has a motion sensor and alarm in it. Normally moving the cover will set it off. $20 - $80 depending on brand, source.

2. Guardian Alarm for Dowco covers. This particularly loud & annoying alarm sits in a pocket within the covers and gets clipped to anything on the bike that would tug out a safety pin on the alarm when the cover is lifted (alarm will continue to go off until they get the pin back in, which is always a PIA and takes at least a good minute if you know what you're doing -- 4 to 5 minutes if you don't). $18 - $30 depending on source.