It seams like the appropriate thing to do but I've never seen anybody mentioning it.  When ordering a pizza you wait for the delivery dude to find your room.  If you are keeping up the appearance of a meeting with a girlfriend, it seams like something that you ought to do.  

I usually do incall, but I've decided that although it may be cheaper, it doesn't put me in the right mood.

Discretion is important, do you (or the provider) want to be seen meeting in the lobby?  Sometimes it is unavoidable like when you need key card to use elevators. A single person passing through the lobby is easier to overlook then a woman meeting someone who has been standing there for 10 minutes.  But a hotel with a bar or lounge could be a much better place to wait.  If your really going for the GFE then how about meeting around the corner at a restaurant or coffee house? Some may even consider that "off the clock".