That is indeed interesting; I guess dogs each have their own way of showing their decision, perhaps Dee can elaborate. I was doing a demonstration at a festival a couple years back. The county sheriff's dept had their dogs there for a demo, and since my Ranger was parked nearby, she (the officer) asked if she could use my truck..jokingly saying.."better not have anything in there, or it will mess up my dog..and your day"..
I told her not to worry..go ahead. She placed a small bag of something atop the right rear wheel..which was a "piece of cake" for the dog.
I have been told this same dept used to have a really great dog, but they had to use her outdoors only. Her reaction to a "hit" was quite often, to immediately 'take a dump'..