The policy is to do it by mail.
I suppose if you're willing to lie to be let in and you're near Bangkok anyway, you might try to replicate the story of a guy who did it in person.
That won't be relevant to people outside Bangkok and people who are uncomfortable with lying to fool the screening people to get in (which may or may not work).
Because of this, I would say forget about doing it in person.
If it became a big thing for people to lie to get in, surely they would figure that out and put an end to that being a possibility entirely.