On this subject obviously I think RAW are pretty clear given charging characters Strain for uncancelled Threats is listed in the combat section in a chart that says that. Lets address RAI as well.

Frenzied Attack, Dodge, Side Step, Body Guard, all Talents in combat that provide either offensive or defensive buffs to combat checks. All of them ranked as well, to provide more benefit per rank per Strain.

Know Somebody, Smooth Talker, Wheel and Deal, Street Smarts, Plausible Deniability, Nobody's Fool, Code Breaker, Defensive Slicing, all social or technical ranked Talents that provide 'offensive' or 'defensive' buffs to social and technical checks, none of which require the expenditure of Strain in order to benefit from them. I think that points out RAI as well RAW that Strain costs were not expected to be charged or utilized as a finite resource in social and technical encounters.

The chart is called "Spending Threats and Despairs in Combat", in the combat section of the rulebook, where it details Threats can be counted as Strain against a player, that's pretty RAW I think.

Here's the problem as I see it. An Obligation roll goes badly for a player and they start with 4 Strain against their 12 Strain threshold beginning of the game. They get into a combat encounter and burn their Strain to the threshold surviving that and they only manage to recover 5 from their checks, so they're at 8. They go into a negotiation encounter and there wasn't sufficient time for the 'breather' and the roll goes badly so they faint?

No. The GM and the players are free to narrate the outcome of an exceeded wound or strain threshold—you don't just always fall over unconscious because you think you're about to get ripped off on the sell price of a blaster after you wasted some guy in a spice trade gone bad. In this specific case, I'd probably describe it as "you start having a crisis" and the player might have some input like, "he goes Joe Pesci on the shopkeep, mouthing obscenities, and storms out of the shop leaving the rest of the party to conclude the transaction." Then a fellow group member gives him a Snickers and everything's all right.

If you aren't going to bother applying the mechanical effect in the RAW for exceeding Strain threshold then why count Threats as Stain at all? Seems to me you could just easily narrate a bad deal and not count Strain at all and still suffer the crisis.

Those are the "mechanical effects" of strain. The player made the decision for their PC to enter a tense negotiation when they weren't in the best frame of mind for it—likely an unwise course of action but that's player agency for ya. How does the game tell you that the PC lost the negotiation? By the PC exceeding their Strain Threshold. The narration for that is up to the GM and the players but the outcome is that the PC is no longer able to complete the negotiation in a manner that achieves whatever level of verisimilitude the table is happy with. My one example makes sense for a "hot headed" PC. A more mild mannered PC might have a hysterical break down. The cool thing about narrative RPGs is both the GM and the player have the ability to work together to tell that part of the story together.

The mechanical aftermath of the social encounter is that a PC is past their Strain Threshold and makes a Cool or Discipline check to regain strain just like after a combat encounter.

I stick to the RAW because that's how the game was balanced. So I don't impose Strain via Threat outside of combat unless as Kshatriya pointed out there is some avenue for that result contained within the skill in question. Another reason is the rule book makes it pretty clear that recovery of Strain is not supposed to be a big deal in between combat encounters. If one applies Strain for non combat encounters then imo it's unfair to not allow players to attempt all post encounter methods of recovery, like simple Discipline/Cool check, a Medical check, etc. The point being even if you impose a couple three Strain in a non combat encounter, how hard is it to just recover from it post encounter? There seems little point to me so I don't do it, and I stick to strictly combat for imposing Strain for Threats.

Well nothing is preventing you from periodically allowing the PCs to recover strain during narrative portions of the adventure.

They can always choose to go back to the ship to rest.

Heck, give them opportunities to recover Strain via some roleplay options during narrative segments.

Say something like "Well what would your character find relaxing?" and let them go do it.

Bounty Hunter spends an hour blasting the womp rats scurrying outside the city gates.

The Smuggler spends an hour playing some casual games of Sabacc and watching the Twi-lex dancers at the Cantina.

Politico spends an hour idly conversing with some prominent local citizens about the state of the galaxy.

Force sensitive character spends an hour meditating.

That's not the issue though, because it you're just going to let them easily recover it why charge it in the first place?

Because there may be an encounter. And they won't always be immediately able to recover strain or the avenues may not be open to them.

And hey, don't tell me the idea of a PC fainting in the middle of the street from all the stress bottling up inside doesn't appeal to you. At the very least it would be funny.

Interesting. I had no idea there were so many GMs that did not use threat for strain even outside of structured narrative. I assumed that was the standard. Obviously I will use threats to hand out strain. Typically though, it's a lot more fun for my players for me to find more narrative ways of spending those threats when not in combat. But for combat, I might pass on strain just to keep the action moving and not slow down everything.