I can't see that working for low-bar, elbows would be wrenched out, bars would roll down the more horizontal back, and so on. As well, PL uses iron plates, which means a dumped bar will often get wrecked. Which is better than a lifter being wrecked, of course, but think of how many squats are failed in a meet, how many would be dumped, it starts to add up to a lot of barbells wrecked, and a lot of expense to running a meet, and thus to lifter fees etc.