I don't understand your distinction between real and hypothetical here.

Basically, my understanding of acausal trades is "ancestor does X because of expectation that it will make descendant do Y, descendant realizes the situation and decides to do Y because otherwise they wouldn't have been made, even though there's no direct causal effect."

If you exist simultaneously with another agent (the 'real agent' from the grandparent), you can sense how they behave and they can trick you by manipulating what you sense. (The person might reflectively consider whether or not to punish you, and decide the causal link to their reputation is enough justification, even though there's no causal link to the actions you took, but try to seem unthinking so you will expect they'll always do that.)

If you're considering hypothetical descendants (the 'hypothetical agent' from the grandparent), though, it's not clear to me how to reason about their appearance to you now, and particular any attempts they make to 'appear' to be stupid. But now that I think about it more, I think I was putting too much intentionality into 'appear'- hypothetical agent A can't decide how I reason about it, but I can reason about it incorrectly or incompletely and thus it appears to be something it isn't.