Re: I don't really have much sympathy for people who fall for such tricks
At one time the CPU power of certain IBM computers could be increased basically by setting jumpers - whereupon everything cost more.
Funny, I just knew that would be the first response! Those systems, of course, were the ones rented by IBM (they didn't sell systems in those days) and you paid a license for the power you used. Just like today where applications are licensed according to things like the number of CPU cores. Even then it would have been obvious that by changing the jumper you were getting something you hadn't paid for.
Back in the 80s there were stories about some minicomputers (DEC? I can't remember) which had a similar trick. Due to a shortage of small memory boards, some low-end systems were shipped with larger boards which had a chip-select line cut, it was cheaper than losing the sale. If you knew which line, you could reconnect it. Hardly standard practiuce, though.
Remapping ECUs is another case where it isn't "free". The cars sold with increased power often have other systems (tyres, brakes) updated to match. Simply tweaking a map without understanding the consequences can cause many problems, not least when the insurance company won't pay out after an accident. That's why most ECU maps these days are encrypted.
why would they be suspicious of other "performance enhancing" tricks?
Because they're free. You don't get free stuff from big companies, but too many people are still too greedy to see that. If it looks too good to be true (in IT or any other domain) it almost certainly is too good to be true. Just like that nice man offering you candy to get in his car. It might be safe, but why take the risk when it almost certainly never is?