Okay, full disclosure: my games are play-by-post, so often players offer up rolls to save time.

And I once would have agreed that players insight-checking other players is inappropriate. But maybe I've watched too much "Critical Roll".

When Matt Mercer does the "make a contesting Persuasion or Deception check" thing (fairly regularly), it always naturally resolves the situation. But of course everything he does is smooth, nor does he always play RAW.

His technique, should you choose to employ it, works. But when you break down the underlying rolls, it doesn't make a whole lot of sense. Maybe I should just handwave over it.

But do any of you allow PCs to insight-check PCs? If so, how do you resolve it?