I remember these were popular with pager alarms back about 5 years ago.
You stick this unit on your windshield and someone taps on it and the alarm pages you.

People still running these things? From a stealth point should I bother with it or no?

 

Yes, people still use them. I know a few people with AutoPage alarms installed in their vehicles. I like the idea of it, because when you're in places like movie theaters, or restaurants, you can't hear your alarm going off. It's also a plus when you live in an apartment complex, and don't want to jump up and look out the window every time a car alarm goes off. That's when having a key fob that alerts you, is a nice (and useful) feature.

 

I think you misunderstood me. I have a Compustar but it's got this little paging unit that gets stuck on your window.
Basically someone knocks on this part of the window and it pages you letting you know someone is paging you.

 

Most compustar comes with those. Its up to you to use it or not. It does not effect if a alarm is installed stealth or not.