If your dog is really determined not to stay put, nothing will hold it. About ten years ago at Ingleston our dogs were benched at SKC. We were by the ring when we heard an announcement over the tannoy asking us to return to the benches where our dogs were "distressed." The only problem was, the benches were halfway down the tent. The dogs had pulled their benches down and were dragging them along by the benching chains. You couldn't really say they were distressed as they had the biggest grins on their faces. That was when we started using crates instead of benching them.

On the soft crates, we use the pegs after one incident where one of ours decided it was fun to roll the crate around the showground like a mouse in a wheel!!!

I have used a soft crate thanfully we were at home.
I left our welsh in the other room and before I could turn around she was out.

I have a soft crate for Indy, for the rare occasion of us being at an agility competition. She settles down beautifully and will curl up and sleep until I take her out. If I leave her out of the crate and just hold her on a lead, she is terribly annoying, attention seeking, and canot settle at all, and as a consequence she gets tired too early in the day.
The soft crate was definitely a good thing for her, but as said, the competitions are the only time we use it.