1. If you refer to these methods as “outlandish”, I have a hard time believing you truly validate the machmirim.
2. “Where do you draw the line”. Ok, valid question, but whats the answer ? An exhaustive check just can’t be mandatory, because its too outlandish? This is not a question of chumra, but of being certain of the validity of the checking method. We are not talking about being machmir on certain shitos, but about being sure, to the extent halacha requires, that you’ve avoided the problem. “Extremism” in this case might be the responsibility of all.