I bring my GSD to Petsmart, Petco, Tractor Supply & Stienhousers (feed store). I never ask. I am 100% aware of my surroundings. If Mr. Rude with Princess Yappy are in an isle, I'll go down another one. If the Ole' Lady who lives in a shoe that has so many children she doesn't know what to do, is down one isle, I'll go down another. If there is someone that has brought a cat - I'll stay FAR away. A trained dog on a leash in an isle is a great distraction. A person reading lables with no pet, another great distraction. A person who asks permission to pet your dog, is a great socialization tool.
My dog is working from the time I enter the door - always at a heel. The only time I let him off heel (but still on a leash) is if we are 'searching' the store for hubby. And we only play that if the store is fairly empty.
I think it's a very good tool for training, as long as you keep your wits about you. I always purchase a little something while I'm there, because sitting in the line waiting to pay is a good tool as well. I don't permit the employees to treat my GSD.
Hondo Von Dopplet L Bauernhof "Hondo"- GSD
Lilie's Tug McGraw "Tug" - Golden Retriever
Maggie - Mini Dachshund (Rescue)
Lonestar Pivo - Texas Blue Lacy
Ashe - Barn Cat
Katie / APHA