Generic here but thought about getting one of the sirens that attach to the cover and bike...take off the cover and it squeals. Then they'd have to deal with my RS siren. I know, a little paranoid but I'd rather have them steal someone's Goldwing than my Black Beauty.
I used to when I first got a tourer but it takes alot of room, is a hassle, scratches the paint in the wind when the bike is dirty on the road and have really never had anyone mess with my bike that I know of. I got insurance too.
I do just to keep people from seeing my bike w/o having to lift the cover when parked at a hotel. Often, the more "bike friendly" ones let me leave it parked under the canopy at the front doors too. I always ask when I check in. Not really any extra security, but it deters most folks from messing with it. I just bungee the cover to the tourpack rack when underway. It's light and the airflow gives it a chance to dry a little if it's damp from dew or a shower.