A thief cleverly deterred is a thief angered. They may decide to do gross vandalism to your property to "teach you a lesson about who you're messin' with" for a cheap laugh. They do not take well to being schooled. Nasty little urchins...
If you have to have such accessories then a recessed or understated install is usually best; it isn't glaringly calling for thievery, and it looks from the git-go like it will be a pill to quickly remove, meaning the would be burglar will walk and leave it be.
When I parked in a bad section of the city where I worked I used to remove even my radio antenna and shove it under the seat, and put it back on at the end of the day for the drive home.
