chances are the guard was just a contracted guard and not a federal officer...i have run into that before (i was the disabilities assisitance officer at the federal building/facility where i worked)..many times the contracted employee "rent -a-cop" aren't familiar with all the reg's.

now on the otehr hand IF it was a federal law enforcement officer...thenthe guy deserves to be written up and sent for retraining because there is no excuse for that.

personally i file a complaint. it is not acceptable either way as the service dog should be allowed access.