Given 12+ years requirement with tech that was initially released 6 years ago, the only "non-local talent" this listing would bring in are time travelers from the future.
Note that I'm not just talking about US. Most countries in Europe have the Labour Market tests requirement before a foreigner can be sponsored for the position.
Whoever issues the letter assumes liability for what they attest to.
It's not like people don't lie on these forms and get falsified evidence. There are cases of people getting caught, and people who did attest to the falsified evidence have had their green cards revoked and deported.
Kinda like IRS I guess.