The more I think about it, the more I believe that partnerships that are at unfavorable vulnerability ought to tighten up their bidding. But not necessarily the opening bidder, in the example I gave.
Someone needs to OPEN in order to get out information. They're not hugely vulnerable to doubles, because doubles of opening bids are usually for takeout. So you can maintain your opening standards when vulnerable.
It seems that it is the RESPONDER that needs to tighten up standards, e.g. respond at the one level with a full six points, at the two level with a full ten points, etc. Many otherwise makeable contracts are lost because dummy didn't have enough high cards to provide "transportation," and these are situations you want to avoid.
Also, one needs to be more careful about COMPETITIVE bids. Weak two bids need six cards, not five, and a good suit. Pre-emptive bids need two honors, not just seven cards in the suit. Raises of suits need honors to go along with spots. That's because THESE bids are most likely to be doubled. And if they are successful, the penalties (500 for down 2, 800 for down 3) will be large relative to the opposing game you are trying to "save."
A competitive bid that requires a high level of caution is a takeout double in the direct seat. If your partner has nothing, opener's partner will redouble, then (probably) double anything your team bids. At unfavorable vulnerability, you will need very good distribution (singleton or void in the opener's suit) for the likely penalty to be less than the game or slam the opponents can make.
Is it right to refrain from making a takeout double in borderline situations?