I draw the line at this... can society justify locking the person up in a funny farm or not? If the answer is no then they shouldn't have their rights taken away. If joe coocoo clock is allowed to roam freely, whats to stop him from harming people? If someone is that dangerous than blocking lawful access to firearms is not any kind of a realistic safeguard. I find it hilarious that there are likely people rolling around, legally driving automobiles, for example, that were probably "involuntarily committed to a mental health facility" at some point during their life. It's OK for us to let them drive something they could mow down 10 people with, but we're gonna shit our pants if he gets his hands on a GUN!!!
I agree its definitely tricky ground, though. You crank up the sensitivity on MH as being a disqualifier and then nobody wants to get help. Not so much an issue with the clueless general public but there are craploads of vets around with PTSD that are already scared of the prospect of losing their guns if the state "finds out too much" about their condition.
-Mike