Well, that question is hardly unique to this forum.

My own preferred tactic depends on whether I consider someone capable of making an informed decision about what they are willing to try to handle -- that is, they have enough information, and they are capable of making such judgments, and they aren't massively distracted.

If I do, I tell them that there's something I'm reluctant to tell them, because I'm concerned that it will leave them worse off than my silence, but I'm leaving the choice up to them.

If not, then I keep quiet.

In a public forum, though, that tactic is unavailable.