iserith
Magic Wordsmith
I believe my examples make it clear that its not happening arbitrarily - and every effort is made to be fair. However, some folks will insist on making decisions based on player-perceived advantage, regardless if it is appropriate for their character, such as the classic low-charisma, no socials skill character being played as a debonair charmer by the player.
I think that whatever is "appropriate" for the the character is up to the player of that character.
Again, they're welcome to try but simply coming up with a good idea as a player doesn't mean their character has the stats, tools, skills and/or background to succeed reliably.
And that's where, in my view, it matters. Be as debonair as you want, but if a given approach to a goal is deemed to have an uncertain outcome, then you will be rolling and you won't do as well, on average, as someone with the higher ability scores or particular proficiencies. What I would try to avoid is telling the player how he or she "should" be acting. It's not smart play to take a lot of uncertain actions that line up to areas in which the character is deficient - assuming aiming for success is seen as smart play - but that's up to the player of that character in my view, not anyone else at the table.
And even then, this only become a problem if the player complains about the lack of reliability - after all, they had the chance to choose different stats, tools, skills and/or backgrounds that would benefit our hypothetical character's social role and for whatever reason, chose not to.
I would find that to be an unreasonable complaint.
Thankfully, we have a solid table with understanding folks - but its not always been like this and when a DM doesn't wish to take on the responsibility of arbitrating such situation then introducing a mechanical element can be an option. One advantage being that, by removing the DM - the 'human' element and letting the dice 'call the shots', the drama that some tables seem to find in personal confrontation can be lessened. Personally, having tried such methods and gained mix success, I'm in favour of the DM simply stepping up but each table and DM's style are different.
It seems to me the "personal confrontation" is the originating problem created by people trying to tell others how to play their characters e.g. "Someone with Wisdom 8 wouldn't do that!" If people don't do that, then the problem such as it is becomes one of mechanical effectiveness which itself can be mitigated by a number of character resources (Inspiration being one of them).