dog sneaking on/off bed

Question
I have a dalmation about 8 years old that always is going on the bed to sleep
when we are gone.  When it hears us come home she gets off to greet us but
leaves obvious hair and foot prints(and the worst SMELL) on the clean bed.  
She is my girlfriends dog (yes she used to let it up to sleep with her every
morning) but now sinse it is getting a little older and smellier we are trying to
keep her off completely.  I cant catch her in the act, and scolding her after
seems like she acts as she has no idea what happened.  How can I keep her
off the bed, without closing the door to the room. Thank you, Robert

Answer
Closing the door is the obvious way to keep her off the bed and out of the bedroom, but if you don't want to do that, then you need to put up a babygate to keep her out of the room. Scolding her after the fact is useless as she will have absolutely no idea why she is being scolded, particularly since she is doing something that she was allowed to do for years.

You could also put a blanket on the bed just for the dog, and bathe her every week or two to cut down on any odor. :)