I read it a long time ago...probably the first version. I thought the punishment stuff was ridiculous and unnecessarily harsh. And at that time, I was training more compulsively too. LOL. Someone bought me that book and I never picked it up again.
I think placement cues are a good thing to teach a dog, if for nothing else, for convenience when you want them to move. I don't think vague terms like leadership are very useful. I have never insisted on a dog waiting to be invited onto a piece of furniture and have never had any issues with resource guarding. But I have taught them to get off when asked or to "scoot over." LOL.
Toker is so cute. I think way back when she first came to live with me, I asked her a couple of times to wait until I got into bed just so she wouldn't go on my half. I'd get situated, then tell her to come on up. I wasn't too consistent or too particular and couldn't have done that more than 2 - 3 times. To this day, while I'm still brushing my teeth before bed, she will sit on the floor by the foot of the bed and wait for me. It's almost like she taught herself. But, after the morning potty break, she sometimes wants to go back to bed and she just goes in there by herself and gets on the bed. I couldn't care less.
I think other things that you do...other training makes a difference in things like resource guarding furniture. If you teach a dog basic obedience, have them sit and wait politely for dinner or to go out the door etc, etc....that transfers to other behaviors. (I think they get better and better at generalizing, the more they're trained) So, IMO, picking one single thing like not letting a dog on a bed uninvited isn't going to make or break anything. IF, however, someone has issues with their dog regarding getting off furniture, then that does need to be worked on specifically by teaching placement cues. That is something that should be taught in the first place....just part of good manners.