As far as I know, this site doesn't associate itself with any specific regional dialect of Spanish, so (IMHO), any answer could be considered valid as long as it:
- ...reflects modern in-use Spanish, and doesn't use any archaic expressions.†
- ...specifically mentions the regional usage of non-universal expressions.
†Of course, this wouldn't apply to questions where the asker is specifically looking for archaic expressions for historical or cultural reasons.
Any question that could meet these simple guidelines would be pristine to say the least. Unfortunately, things can't always be perfect, and we shouldn't expect them to be.
There will be cases in which an answerer won't or can't supply the exact usage of an expression. In these cases, care must be taken to not jump to conclusions and assume errors. I'm of the mindset that unless there is specific evidence that an answer is incorrect, it should not be downvoted or flamed.
Rather, I feel that, as a community, we should collaborate to determine regional usage either by a process of elimination (e.g. a person could comment to say that
expression X isn't commonly used in
region Y, and help give context), or by providing further research.
In short, we can't afford to assume things, because what may sound extremely awkward to me, could sound perfectly fine to you. When in doubt, the community should try to work together, since that's what makes Stack Exchange so awesome after all.
Just my 2¢... :)