My worry with the transponder off option is it will be fine for "honest" gamers but that some people and probably the very people you are trying to avoid will just analyse their network and so they will have a good idea who you are but you will be oblivious until it is too late.
I do understand Jeff's concern too. Not sure if it would be an issue but sometimes once open the box there is no going back.
I understand your own concern, even though how this is achieved is beyond me. Fortunately, I also think this will be beyond the majority of gamers who, like me, just want to play a game. As for the minority who get their jollies from doing this kind of thing, stuff 'em. If that's what it takes to 'do it' for them then I have nothing but scorn towards their ilk. I doubt, though, that their numbers are enough to seriously detract from the benefits I see from the use of transponders. I understand that there are other exploits being used in the game that utilise this tomfoolery but still the game continues.
I doubt this is a Pandora's Box scenario. If using transponders does not work out to the benefit of the game, I see no difficulty in 'putting the lid back on' and returning to the status quo.