I use "Yes" as a positiver marker. Yes, is not praise and definitely not a release. Yes, is simply a marker for correct behavior. Praise is an enthusiastic, "Good Boy, super, brave, etc. Praise is part of the reward, but praise is also not a release. My release word is "OK." Praise and petting may come before I release or after. But the dog never breaks on praise alone. It can be subtle, but a very important concept to understand in training. I can tell my dog to do something, mark it with a "yes" and even praise him up with out him deviating from what he was doing. It can be guarding after a bite and an out, where I praise but do not release him to re bite. It could be doing a send out and downing him half way and praising from 50 yards, but not allowing him to break his down stay.
For me, a positive marker just calmly marks a correct behavior. Praise is one component of the reward structure and tells the dog he did a really good job. It is not an opportunity or an excuse for the dog to break or release. After I release the dog I may praise and reward even more energetically. The dog only gets released when I give the command for him to release. Teaching a dog that praise is a release or even pairing it with a release causes problems and issues down the road. They are 3 distinctly different things.
“Beware of false knowledge; it is more dangerous than ignorance”. George Bernard Shaw