In the August 2011 Marie Claire magazine, ESPN reporter Erin Andrews includes these safety tips for protecting yourself, and your privacy, in hotels:
1. If the clerk says your hotel room number out loud, and others hear it, ask for another room;
2. If you get a room with an adjoining room, prop a card against it so you can tell if it's been opened;
3. Cover your hotel room's peephole with a Band-Aid;
4. Put up the "Do Not Disturb" sign - no one needs to be in your room. If you need towels, call and ask for them.
Additional tips from me: Don't accept a room on a ground floor with an easy window, balcony or sliding doors to parking areas; exit an elevator if you ever have a concern when anyone is entering; and book a room for 2 even if traveling alone.