Gibby just had his AG expresses and they said he had a bunch in them. You know...his express a lot of times when we dont' want them to...such as in the back seat of our car...........................or while climbing on DHs lap when he is sitting on the lounge chair watching tv, and a few other times. I have never seen him scooting....or doing anything except possibly looking at his but once in a while. Bubby used to get hers expressed once in a while...and Ollie used to do his own in his bed....of course you always knew by the great smell! SHEESH!
We see several dogs at work that end up expressing theirs when they are scared...had tons of little dogs do that while carrying them to the back. INCLUDING Gibby who we were trying to get into a kennel and he wasn't buying it..... he paid us back!! 
I do think its interstesting that all three Danes had a firm stool ( Gibby most of the time except for when he is having problems ) and they still had AG issues. I had always thought that if their stool is nice and firm it helps to put pressure on the glands to express along the way out...but not our Danes....