/snip
For myself, one of a few different scenarios will determine A) if I ask for a roll and B) the result of success.
1. If I don't have an agenda when the PC wants to get a ride to Port Royal (or whatever), the PC will get them there. (no check)
2. If the players want a ride but the adventure is about them taking time (e.g. walking) so as to present a time constraint later on, then they walk and the NPC can't help them (no check).
3. If part of the adventure is a stop-over in Haxel for an encounter or two, then the NPC can only take them as far as Haxel on a success, and they are walking to Haxel (on their way to Port Royal) on a failure.
I really hate to do this, at the risk of Godwinning the thread, but, how is this not railroading? The results of the player's actions - attempting to get a ride to Port Royal (thank you for that btw, I'd NEVER remember the actual proper noun place

) are determined, not by the in-game reality, but by the meta-level of the DM's wants and needs. The DM needs the player to walk, so, regardless of anything else, they will walk. No NPC will help them, and they won't even be able to make a check to change that. Or, conversely, the DM needs the player to stop in Haxel, so, again regardless of the players's role playing, they will only get to Haxel.
As a DM, I am really uncomfortable inserting myself into the fiction like this. I do consider that to be far too heavy handed and makes me extremely visible to the players. And, frankly, I don't WANT that level of responsibility over the game. I want to be surprised. So, if the players convince someone to take them to Port Royal, then, well, that's what happens. What I, or the adventure I wrote, want does not matter one whit.
As a player, I would be extremely frustrated as well. It's pretty obvious that the DM is road blocking here and forcing results, again, not because of anything the player's did, but, because the DM wants a certain outcome and will simply manipulate the game and, IMO, abuse his authority as DM, to ensure that a specific result will happen.
To me, @D&D_Reborn's three examples that I quoted are 100% the reason as a player and a DM that I want social mechanics. It makes the game far more transparent and allows the game to flow far more organically with everyone's input being taken into account, rather than just the DM feeding the story to the players. OTOH, I've absolutely played with players who 100% would adore @D&D_Reborn's approach. So, there's nothing wrong with it and it's certainly something that players will enjoy.
Just not me.