You taking a dump would leave a higher heat signature than your cfl. An IR camera doesn't give the po-po's superman-like x-ray vision. Infact, Infrared cameras see in the night using an I.R., Thermal Imagery sees heat (in 1 degree incraments). Thermal Imagery will not see through walls either. How it is used to bust growers is when its used in conjunction with other investigative techniques, as a poster has stated- electricity bills (including the info from the power company that your useage seems to spike, usually for 12-18 hours at the same time daily...), all your old soil balls, smell, informants and whatever other info they got on you. Police also LOVE to tell you mis-information.... "we're gonna let narcotics know about you", (or my favourite that was told to the neighbours of some growing friends "there's gonna be 400 grow-ops busted this spring.... ". Really. 400 busts? well, THAT will really bog down the court system here for the next 10 years YA RIGHT. I have been narc'd out by an ex-friend.... never got a visit. A friend who's grow WAS busted, only got his babies killed, wires cut, and bulbs smashed... no promise to appear or anything. A cop seeing your grow unit and saying its for dope, is tantamount to him coming in to your home, seeing a rifle on the wall and saying "I'm sorry sir, I'm gonna have to book you on suspicion of murder, on account of that rifle up there on the wall...
Grow your veggies, and/or your dope. For fuck sakes people, Cops are only PEOPLE IN UNIFORM! They have no special rights or magical powers.