Influencing the PCs

Influencing the PCs is mentioned on B359:

When an NPC makes a successful Influence roll against a PC, the GM should apply the NPC’s margin of victory as a bonus or penalty (as appropriate) to the PC’s die rolls

It does not say for how long that MOV should apply. This guideline is later found in Social Engineering under Intimidation on page 68/69

Make a reaction roll for potential combat (p. 68), with an added penalty equal to the NPC’s margin of victory.

Apply the same penalty to the PC’s initial roll to attack, reflecting lack of confidence.

This at least means that the penalty expires after ONE roll in the case of Intimidation, and the only "appropriate" roll to penalize is an attack (presumably against the one who used intimidation, not other targets)

That may not apply to other influence rolls: they could last for multiple rolls, or only apply to non-combat ones.

A remaining hole is how long the potential penalty applies if the intimidated person does not attack that day. One would imagine after several years go by since the last intimidation that maybe that penalty would evaporate.

Application time

One second

The expansion of B101's Shtick notes on MA51 gives the example of chiburi where Intimidation can be done as a free action or get +4 if using "entire next turn" to make deliberate attempts.

This seems to imply that normally it takes a maneuver (probably akin to a Concentrate) to use a skill like intimidation if one lacks a shtick such as chiburi.

several seconds

MA130's Mind Games option The Contest of Wills involves a Regular Contest instead of a Quick Contest, and can be rather long.

Intimidation or Mental Strength are subbed for will here, and in addition to penalizing a reaction roll, MOV also penalizes attack rolls if they do attack (though it is unclear for how long)

Quotes

Kromm referenced it in 2011: http://forums.sjgames.com/showpost.php?p=1145230&postcount=30

Remember that PCs are affected by NPCs' Influence skills. However, to make the experience more roleplaying than rollplaying, this isn't handled as a binary "NPC does/doesn't gets his way" test. Rather, the player gets the option to go along with the NPC's goal. If he decides to hold out, that's fine! But in that case, he suffers a modifier equal to the manipulator's margin of success should he try to act against the goal that the Influence roll was made to support. See p. B359.

In light of this situation, it's game-mechanically sensible to allow Resistant; this is just a specific case of "Mental Resistance" (p. B81). "All Influence skills" is Common; the topmost, Immunity level is named Indomitable [15] (p. B60). Thus, +8 to resist costs 7 points and +3 to resist costs 5 points.

I'd split that further into refined (Diplomacy, Fast-Talk, and Savoir-Faire) vs. unrefined (Intimidation, Sex Appeal, and Streetwise), each with Immunity [10], Resistant (+8) [5], and Resistant (+3) [3].

An individual skill would have Immunity [5], Resistant (+8) [2], and Resistant (+3) [1]. The point being that this is not a skill . . . even a Will/E skill would be too costly for what it would do, as Will+3 would cost 8 points, more than any of the above Resistant (+3) traits.

I wouldn't link Resistant to Appearance. What I would do is turn the Appearance modifier to Sex Appeal into a differential one based on the mean ("Androgynous") reaction modifier: -6, -5, -4, -2, -1, 0, +1, +3, +4, or +5.

Someone who's Attractive (+1) gets +1 vs. Average (0) people, +2 vs. Unattractive (-1) people, etc., but for instance -2 vs. Beautiful (+3) people!

Someone who's Unattractive (-1) gets -1 vs. Average (0) people, -2 vs. Attractive (+1) people, and so on, but a big +3 vs. Hideous (-4) people!

This would represent people going for the most appealing partner they can get, which with people finding their level and establishing "leagues" means that the beautiful people will tend to stick together.

Then there would be a quirk, "Low Standards," that lets the user of Sex Appeal waive this modifier against you when it's a penalty:

"Others never suffer a net penalty for relative Appearance when using Sex Appeal on you. If it has the right body parts, you're interested!"