Actual impropriety would be if she somehow cheated in order to win both baskets, and as long as that didn't happen, I guess she's in the clear. But in an organization like this (volunteer, right?) I'd think you would want to avoid even the appearance
of impropriety, and thus make a rule that the person who draws the tickets can't have bought any. I'd think that would be a small sacrifice for, say, one of the officers to make each year, to bring that much more appearance of fairness to the proceedings.
I also feel weird about her winning two
baskets. Again, if she didn't cheat or otherwise go against the rules, technically she's fine to keep both. I don't think I would keep both, though, I would feel too uncomfortable about it.
Since there are so few baskets, and each basket is worth a lot, I think it would be fine to have a rule saying a person could only win one of them. Yes, the chance of winning more than one inspires people to buy more tickets (thus helping the organization), but this could be offset by ill will if the same person starts to win several of the baskets. Okay, sure, likely that person bought a lot
of tickets and thus gave a lot
of money to the organization, but it starts to feel weird to me--like, they're trying to buy attention or glory or something. People might start to think, oh, why bother buying any tickets this year, Betty's just going to buy 100 of them and win everything.
Maybe the rule could be that you can win one
super-nice basket, and then if your name is drawn again on another basket, you can pick from a group of smaller prizes, and they draw again for the basket. That way you still win something, but the organizers ensure that six different people go home with a super-nice basket (and thus are more likely to participate again the next year).
Of course, I've never won anything in a raffle and don't understand probability that well, so take my advice for what it's worth.