Medical marijuana laws and probable cause: some defense friendly dicta from the 7th Circuit

Marijuana reforms present some interesting Fourth Amendment questions.  In particular, does the scent of marijuana give the police probable cause to search in a state where some of the residents (i.e., medical marijuana patients) can legally possess the drug?  The issue has been litigated here and there but it's still very much an open question and the answer may depend on the particulars of state law  (for example, does the state create an affirmative defense for medical marijuana patients at trial or does it give patients protection from arrest.)  

Those who follow (or even have the occasion to litigate) the issue may be interested in some defense-friendly dicta from this recent Seventh Circuit decision on exigent circumstances and the smell of burnt marijuana:

The possession of a small amount  of marijuana is far from that rare case. In all of the states in this circuit, mere possession is only a misdemeanor.  In fact, in Illinois, possession will soon no longer be per se illegal under state law, as Illinois has begun implementing regulations to permit the use of medical marijuana for qualifying individuals. See Medical Cannabis Pilot Program, ILLINOIS.GOV, http://www2.illinois.gov/gov/mcpp/Pages/default.aspx (visited March 5, 2014). Thus, once this regulatory scheme is in place, the smell of burning marijuana will not necessarily be indicative of any wrongdoing under Illinois law.