This question asks about the UK specifically, but as of now the highest voted answer applies to the US. The person who gave the answer suggested in a comment that a US answer is useful anyway for US-based site users.
Discussions on broadly similar issues on meta.SE (example) seem to conclude that answers that are correct but inapplicable in some way are not useful and should be downvoted.
How should we handle answers that are correct in themselves, but apply to another jurisdiction? We have lots of questions about one specific set of regulations where there are comments or answers that mention or apply to other jurisdictions (example, example). Sometimes it doesn't matter and they're often interesting as comments, but should we be doing something different? One (extreme?) approach would be to make all regulatory questions wikis, so that we could list the regs in each jurisdiction that people are interested in.