"Get caught with a firearm and medical marijuana card and go to prison as prohibited possessor."
Not hardly. Having a pot card does not in any way mean you are a current or past user of marijuana. We all probably know folks w/ driver's licenses who do not drive. I can own an entire shelf of books, but it doesn't mean I have read them, will ever read them or even know how to read!
Invest in precious metal...buy lead \m/