its the same principle of me sitting in my driveway and doing a big smoking burnout.... cops could be sitting out the front of the house watching, but they wouldn't be able to come in and actually do anything (from what i understand, anyway, don't take this as gospely) due to it being performed on public property....
well, they could probably ask you to stop, due to noise/smoke pollution, but i believe it would then be up to the EPA to fine you for the noise/smoke, not the police...