bid on your right is alerted. You enquire and are told it's better minor (ie very occasionally 3-card suit). You then double for take-out. Next hand bids 1NT and partner bids 2 of a major, since you doubled for take-out.Ask and Double
This really happened in a 1998 County Congress Pairs Final. You hold Ax, Jx, AJxxx, Kxxx and the 1 bid on your right is alerted. You enquire and are told it's better minor (ie very occasionally 3-card suit). You then double for take-out. Next hand bids 1NT and partner bids 2 of a major, since you doubled for take-out.
Not liking this you bid 3 and the hand is passed out. To your surprise the Director is called, and the opponents reserve their rights on the auction. In genuine innocence you ask "what have I done wrong?". As it happens 3 goes 2 off for a bottom so the Director isn't called back to the table at the end of the hand.
Just what did you do wrong? I'm a cynical Director at the best of times but I accept there are a lot of quite reasonable players who innocently make this particular ethical mistake.
When you make a take-out double you are showing the other suits or a very strong hand. On this hand you may feel you want to bid, and make what is in practice a very poor take-out double because you can't really play in all other suits. When you bid 3 you are showing a hand better than a take-out double because otherwise you just pass or raise partner. Partner has made a free bid and facing a hand of the strength you have shown would normally be expected to bid again because it sounds like you have game.
...But he didn't bid........ AND you asked about the 1 opener!...
It doesn't matter that you and your partner assume that doubling and bidding your opponent's suit shows this sort of hand because the Director won't accept this (unless it's on your convention card, and even then he’ll ask how you show very strong hands - double and bid opponent’s suit is normal) and he will still rule against you if you asked about the opening bid.
You have three choices:
1) Don't ask about the opening bid when you hold the suit, in which case the opponents can't have any gripe. A hesitation would suggest you could have the suit too. It seems a bit unfair but it is better not to ask and be fixed occasionally than end up in this sort of problem.
2) If you must ask then don't make a take-out double and bid again when you're weak. You can pass partner's 2 
to show a minimum T/O double. The Director would accept this entirely.
3) The expert action would be to pass without hesitating or enquiring and hope the opponents played in diamonds. Even with an opening bid an expert seldom bids with length in opponents suits or holding a weak no-trump for this reason.
For what it's worth you haven't really done anything wrong. But Partner is absolutely fixed by the innocent question about the opening 1 . Simply he CANNOT pass your 3 bid now because the auction suggests you have a game, and your question rules out the logical alternative of pass (even if it’s your method). So DON'T ASK!!