Some Orthodox rabbis allow, or even encourage, members of their synagogues to have their relatives' hametz sold in preparation for Pesah, even without the relatives' knowledge. To me this seems misguided. Why "misguided"? Because I'm being tactful.
Is such a sale really a sale? The certificate that the seller signs usually says that the transaction that's being arranged is a legal sale under both halakhah and the laws of the state that the synagogue is in. I'm skeptical. Would the state recognize a sale in which the seller not only hasn't authorized the sale, but doesn't even know about it? (Lawyers, please comment on this.) Does halakhah recognize such a sale? (Halakhists, you should comment on this too.)
I have heard someone raise the objection that theft might be involved. Dad (for example) might eat the Gentile's oatmeal. That's right--Dad is the thief in this scenario, not the "baal teshuvah" and the rabbi. The rabbi set the questioner's mind at ease: he should still have Dad's stuff sold, since owning hametz during Pesah is worse than theft.
Dad's kid thinks he's sold Dad's stuff, Dad is neither informed nor asked about the sale, Dad doesn't realize a penny from the sale, and this guy has the hutzpah to call Dad a thief. This is a much more serious untethering from reality than mere superstition would be.
And let's say Dad, whom his son loves and reveres because that's what such a pious person does, finds out about this transaction. Dad is an apikoros and therefore unreasonable about such things. "You sold my stuff? What were you thinking?"
"Dad, I did it for your own good. I realize it was wrong of you to steal the goy's food, but owning hametz on Pesah is worse than theft."
"So you're saying that because I have h instead of matzah on Friday night during Pesah, I'm worse than a thief? Although I'm also a thief because I ate food that you think you sold to some shaygetz--maybe even a shvartze." Apikorsim just don't understand what's important (and some of them are annoyed by "goy").
Now let's imagine the "baal teshuvah" didn't tell Dad about the scheme, and the Gentile buyer comes to pick up his purchase, or at least to inventory it. What a surprise for both Dad and the Gentile. Dad and the Gentile have two things in common (in addition to being surprised and not being Torah Jews)--both claim the same oatmeal, and both are probably appalled by this bogus transaction once they figure out what happened. Not only do you think you sold Dad's stuff, but you also think you authorized some stranger to wander into his home. To take his stuff. And what about the Gentile? He probably entered into the deal in good faith, imagining that only the actual owners were selling their stuff. The rabbi and the "baal teshuvah" are acting in bad faith with the buyer by selling stuff they have no right to sell. Also, the Gentile is probably one who doesn't hold negative stereotypes about how Jews do business. And this is how you deal with him? After the encounter with Dad, the Gentile goes to the rabbi and asks what gives. What can the rabbi possibly say that won't sound stupid, cynical, or both?
Another possibility: the Gentile comes over with some deranged-sounding story about having bought Dad's food. Tempers erupt. The police are called. Perhaps the press will print an accurate story about the deal. It would be a fake shandeh. Anti-Semitism on the part of the press!
OK. Maybe Dad finds out, maybe he doesn't. But let's say the "baal teshuvah" has a little bit of common sense left and suspects that such a sale isn't really OK under state law. He asks the rabbi. Maybe the rabbi thinks such a sale is obviously OK under state law because why wouldn't it be? Such a rabbi can be suspected of being short on common sense. On the other hand, maybe the rabbi sees the problem, but encourages the "baal teshuvah" to sign it anyway. Draw your own conclusions.