Sure that most certainly is possible if a grower has blatantly parked a couple of 600s against a wall. But that alone is not enough to get a search warrant which is why you never see FLIR only cases going to trial.
If that were the case, again, that would mean there would be lots and lots of search raids resulting in no grow rooms because lots of other things do cause heat signatures on the outer walls of a house, wall heaters, stove hoods, dryers, indoor furnaces, large wall mounted plasma tvs, saunas, steam boxes, and the list goes on.
The fact is there are only two or three cases where the cops raided when FLIR images were used to get warrants, where no grow room was found. The rest all came from informants: friends, foes, neighbors, the mailman, the meter reader, UPS, FEDEX, friends of friends, ex partners, and others, tipping off the police about your grow op.
Look for yourself, in every instance that FLIR was used, it was after the informant tip off, and it was used to generate the grounds necessary for a judge to issue warrants.
In the rare cases where there are no so called unusual heat blotches, where the power bill is not out of the usual usage range, that is when the police step to the next level of 'means to an end' tactic you mentioned.
These range from apparent accidental discover via: fake burglarys, fake informants, falsefied interpretations of FLIR images, false reports of marijuana odor, false sniffer dog hits, all resulting in meeting the criteria of probably cause.
Again FLIR in those cases is not the first or sole means to an end.
Growers need to focuss 99.99% of their detection avoidance efforts on the security of their networks of friends, odor control, and keeping the power bill to reasonable levels. If you feel the need, line your grow room with mylar.
In the end, with even the most mylar'd IR Blocked grow room, you are still susceptable to the MOST used techniques for generating warrants...
INFORMANTS.
