A survey released by The Ponemon Institute indicates that more than 10, 000 laptops are lost or stolen each week - JUST in U.S. airports! Now add in hotels, coffee shops, and vehicles. I've had a laptop stolen from a vehicle, lucky for me it wasn't mine. Don't worry it wasn't a client's either, my wife was driving my car & it was her laptop. So anyway, now that you know the likelihood of such a theft just do a google search to see how bad it can turn out (We can talk about your data being out there without you knowing in another article).
I am a big believer in encryption, especially whole disk encryption but as in everything I.T. it is a cat and mouse race too. Read about Evil Maid Even after reading the Evil Maid story I'll still use encryption, and whole disk encryption for my important data & recommend it to my clients as well.