Medical Marijuana Question

[Trevor Suich]

I'm currently renting a bedroom out in the home that I own, and one of my tenants recently asked me if he could keep his medical marijuana at the house.  He says he has a Florida medical marijuana card, and he knows I will cancel his monthly lease if he smokes in the house.

My question is this: if police were ever called to my home and found the marijuana on my premises, would I be considered liable under constructive possession?  Would keeping a copy of his medical marijuana card protect me from this provided it did not expire?

Thanks everyone!