I'm going to make the assumption that the people who own the SUV and the house are probably pro-marijuana. I'm not here today to say on which side I stand for that lovely plant. I think everyone is entitled to free speech, especially by way of decals and bumper stickers. They don't harm anything except the car, in the case of a sticker.
What I find so hilarious is that right next to that SUV, tied up in the front yard, was a collie with a muzzle around his mouth. Apparently free speech does not apply to their canine friends.