Originally Posted by
halls120
If you were stupid enough to admit to past drug use in any form of written communication, then yes, you shouldn't lie to a Customs Officer upon entry to the US.
Just because the government might allege at a later date that you lied to the CO, what's their proof? What if they are going on the word of some third party who mistakenly frames you as a drug user?
I would hope that the government doesn't just take someone's uncorroborated word for it (maybe unless they have a number of friends, family, etc. saying "yep I used to blaze it with that guy every day"). But what are the situations where the government goes to the effort of interviewing family, friends, co-workers, etc. of a foreign citizen in, or arriving to, the US? Does it occur for green card applicants or those going down the citizenship path? It seems like whatever those circumstances are would be about the only common situations where it's even theoretically a concern that someone would "rat you out" or that a private communication would surface, aside from some other Federal dealings that aren't common for most non-citizens.
Otherwise if, as noted before, there is no public record of it, there's just no realistic way the government will ever find out. They don't send out investigative field teams for every tourist or short-term business visitor or similar, who comes to the US.