From the good guys over at Spiderlabs :tspry:
More how to stuff
http://blog.spiderlabs.com/2012/10/pentesting-hotels-with-pens.html
That along with this will be super… 
Wild. I need to start rolling with you and getting into this dry erase stuff. 
Most hotels have deadbolts too…
Pretty cool nonetheless.
IB4 some tard buys expo marker at dollar tree and gets the tip stuck/broken off in a hotel door wondering why it didnt work LOL
Security in the hotel room is shot to hell when you give minimum wage maids and workers master keys to every room. I’ve never been robbed by a maid, but if a theif really wants in, they just have to show up while the maid is cleaning and shut them up or social engineer their way in. If you’re in the room, put the deadbolt on. Don’t leave anything in the room that you value highly.
Someone mentioned other locks on the doors? lol
I know someone with a marker setup and the code to do this. Was playing with it for a project and its fun but the lock breaking methods its using is way above me. I read the white paper on all that and other notices and its amazing.