What wrong with getting a get out of jail card?

If the ban on marijuana is illegitimate(morally constitutionally), and people are in jail unjustly for something that shouldnt be a crime(but rather a medical issue no matter how you look at it), then doing whatever to keep people out of jail including lying to doctors to get cards is justified.

A more extreme example would be lying to the german police about the existence of jews in the house.