Despite the temptation to slightly increase my chance to win something, I don't think we should disqualify someone after the fact. If he was eligible to win at the time of the draw, then he won. It's our fault, not is, if he was allowed in the draw while he might shouldn't.
This would lead to frustration and an impression of unfair treatment for the winner.
Full disclosure... I did answer the question in question, but admittedly at the time I was on the fence as to whether it should be closed. On the one hand, it seemed a little trivia-like in its wording. On the other hand, Earth had seen a couple of invasions and someone who hadn't caught all the episodes might not be sure if Nixon was still President. I ...
His prize has already been ordered, so he's not going to get his prize taken away.
If there's enough of an outcry about this from people, we can award double winners on another day or draw another winner from that time frame.
The rules only state that a question be open to be considered for the prize, which the question obviously was at the time of the ...
I hope not, because everyone who has had their prize already sent out may feel slightly hard done by at not having the same opportunity. :)
That said, the Answerama site is pretty unambiguous at saying the prize(s) will be selected by SE, i.e. not open for personal selection.
It shows all tags, and they all link back here. So a question tagged futurama time-travel shows up with both tags (though the first is redundant) and the second tag is a link to all SF&F questions tagged time-travel.
Surely it would make more sense to (a) omit the futurama tag (and if that leaves many questions showing no tags, what harm?), and (b) have ...