I see some prettuy stupid things in the mountains also, including folks on Whitney in the past who had no idea any sort of permit was required.
Regarding the use of signage, here are the signs at the Maroon Bells in Colorado: Do they work? Perhaps, but every year, these difficult, unforgiving mountains still claim lives.
As discussed already, it possibly could help to have as a requirement for a permit, a short orientation by a Ranger, etc going over some of the inherent risks of climb, AMS, etc. Certainly can't hurt.
