Your last sentence highlights the problem. I can have a bot that posts for me. Also, if an authority is in charge of issuing the certificates then they have an incentive to create some fake ones.
Bots are vastly more useful as the ratio of bots to humans drops.
If it is linked to the Internet then it’ll be hit by crawlers. Their “trap” isn’t any how many show up but how long each bot stays on their individual site.