i'm pretty sure on this, but not completely, even fi they did find your grow, and had to leave they couldn't get another warrant because the 'evidence' was found under diffrent circumstances... the laws have lots of loop holes in them.

like i said i'm not sure, but i think i remember hearing that (i used to watch crime tv [court shows, forensic investigation, cops, ect ect i used to want to be a cop ROFL...]) if i am right it also may vary by where you live.