Well, I've found that getting physical with my dogs works when it's applied correctly. Example: Spud has begun to bail out of the truck when it's parked and he sees something he wants to investigate.
This evening I loaded the dogs in the truck and put the tailgate up. Purdy stands in the box, Spud gets on the tool box. Didn't clip them in. Just told them to "stay" while I unloaded some items from my wife's car and took them into the house. Didn't want the dogs under foot at the time. Next thing I knew, Spud races into the house ahead of me.
I put the items down, called him back out to the truck. He wanted to load, but the tailgate was up. I grabbed him by the nape of his neck and his hips and threw him back into the box with a modicum of force over the tailgate. He looked [beeep] surprised and was again told "stay". He did after that.
I decide when he gets out.
Before the tailgate ever comes down, my dogs have to sit and then stay when it comes down. There is no unloading without an "okay" command. It's for their safety.
Purdy got the same treatment when she was about Spuds age. She won't unload without a command.
And I, too, will dominate/discipline either dog when necessary by holding them down by the neck and shaking a bit. They always get up with an "I'm sorry" look, head down, tail wagging and wanting to lick my hand.
I don't beat my dogs, but they sure better mind. I'm just like most of you guys