Largely I'd say it's a horrible idea.
First, there's no way we're going to get enough training to really be able to make the eval for a yea/nay on a hold.
Second, even if they did give us the training, we'll never spend enough time with the patients to really do the eval.
There are, of course, some patients that blindingly obviously need a hold, and I've been doing it long enough that my gut is relatively reliable at picking out the less obvious ones.
Putting someone on a hold, though, is a HUGE deal, and my gut should not be the arbiter, nor should anyone elses, and you're kidding yourself if you think that it won't devolve to the "appropriately trained" paramedics ignoring that training and using their guts (Albeit, the training MIGHT improve the accuracy of the gut reaction). Unlike psychologists, psychiatrists and social workers who typically make the decisions about holds, all of our training is about making a quick decision.
If even one person is put on a hold who shouldn't be, then the entire program is a bad thing, and many more than one will.
PS: Having said all that, a few weeks ago I had a call which wound up being an administrative nightmare, all told I spent 3 hours on the phone, doing paperwork, and meeting with the state EMS office (not to mention pissing off people in four different facilities), all of which could have been avoided if I could have placed the hold. It would have been nice to have the ability, but even still, I don't trust myself with that power, I sure as :censored::censored::censored::censored: don't trust some morons with medic patches I know with it.