Having used one i do get your point but having been on the shit end of people shooting with a thermal while i was walking into a hut in the dark i was genuinely scared for my life. The sort of people that poach are not the most careful. And its not far to think they would shoot at a shape if they would shoot at eyes. Also interestingly enough human eyes dont reflect. So i would prefer spot lighters as they give a warning the are coming.
Also have seen them used on the tops after dark and reported hunters to police and as far as I know nothing eventuated. The hunters flew in by chopper right next to where i had hiked to and set up camp and first night they proceeded to shoot a young 10 point and only take its head. I heard the shot at near midnight and the next morning i walked past there camp and they couldn't tell me how good the thermal was. I hiked further in and came back out to a tonne of backcountry wrappers shoved in a hole and a heap of beer bottles left in the tarn. I packed all of these out as i hadn't found a mature stag so pack was empty enough. Called up the chopper company and they reluctantly passed on party details and let me know they wouldn't fly them in again (due to rubbish mainly).
Anyway after the pointless waffling I think they have a place and are progression but the do also provide a means to do the wrong and dangerous things easier than other options.