I just read this article and it's interesting how theives use a laptop to hack (possibly with brute force) cars equipped with RFID
keyless push button start to steal them. It says it only takes as much as 20min to hack a car then drive away with it
http://www.dailytech.com/article.aspx?newsid=2117
Perhaps it's a good time to get one of these:
Here in canada it's easy to tell which ones have that option: since there are only 3 options to choose from. Base model, Fully loaded, and Fully loaded with Nav. This makes it even easier to distinguish for theives

The base model doesnt have it and you can tell that by looking to see if the car has fog lights; If it has no fog lights, it's the base model, therefore, it doesnt have RFID push button start.