That is one of those questions with no definite answer If you are in an area close to a Can.Club the chances of them giving you trouble are slim but if your in an area where its a 'point of focus' for the cops then regardless of the license they are likely to find a reason to confiscate it and hold you for a day.

California made it medically accepted and it is surprisingly easy to get weed with the license but no matter what the counties who legalize have to say the federal law still holds it fully illegal. The feds CAN arrest you and go after you, but they rarely do, all this beauracratical(sp?) bullshit bah I hate it.