Actually I would normaly agree with you but because "I" of all people (little ole me)took this dog and stood him in a stand (with a treat of Course)and examined his ass without nearly a grumble or even a dirty look(although I did not touch.....LOL), I will have to question any revenge on a decent groomers part!
I also was at the vets with him and heard techs talking about his gentle nature "within reason"(we can only expect so much of our dogs...lol). I believe he was expressed for the extra charge but at this point can not say for sure. Why he was at groomers I can not say.
I haven't taken a dog to groomers for over a decade but still If one does take them there, should the anals be expressed just to be expressed........
And honestly even if he was about to take a groomer out does that give them a reason or the right to express glands that are not needed.
Although If I was a groomer I may understand that....:D