Derren said:
So how do you decide if that works or not? Abitrary decisions? "Rolling under the ability score" which when the attributes are maxed is a auto success?
Role-playing, augmented by ad-hoc dice rolls (based on my judgment of the likely chance of success, modified by the character's stats, the player's described actions, and the vagaries of the specific situation) at key junctures:
After I make sure that the distant relative of the lord can't attend the ball
die roll: say flat 50% chance (or some other number, at the DM's discretion, depending on the specifics of the situation) of findng such a relative
I forge an invitation to it and pose as him.
judgment call/die roll: base his chance of success on the previously-demonstrated background and MO of the character -- if he's previously been played in a way that would suggest this was within his skillset he can do it, otherwise he can't
With the mask I will be wearing no one will recognize me as they haven't seen that relative in years.
die roll: each person he talks to at the party has a chance to recognize him as an imposter -- the chance varied person to person, from very small (1%, or even no chance) to significant (perhaps 1 in 4 or 2 in 6), how well the player roleplays can affect these rolls
To make the disguise more convincing I will higher a local harlot to pose as my concubine.
When I am in I will mingle with the rest of the guest for a while (note, keep on eye on the harlot).
roleplay this out -- depending on the character's background, probably assume that he knows where and how to hire a harlot, otherwise that's another step of roleplaying
I made a little research about the country the relative lives in so I probably can answer basic questions if someone asks. If not I'll make something up, those people won't listen anyway.
assume the character is able to acquire basic info (unless there's some reason why this info wouldn't be easily obtained, then make an ad-hoc die roll as appropriate); beyond that, roleplay this out -- if the player plays it well he'll succeed, if not people will become increasingly suspicious
After a while I will talk with the lord (note make it so that it would embarras him when he doesn't talk to me) and after a little small talk admire his wealth and hope that he tells me where the real treasure is kept.
roleplay this out -- as above
After that order a lot of wine ovwer the evening (pour it into some plant) and pose as drunk and drag the harlot to a hidden place.
roleplay this out -- as above
There knock her out and tie her up. Can't let her wander around unattended.
combat to knock the harlot out; if that's successful we'll assume he knows how to tie her up
Then loot the lords room any any other rooms which can be reached safely
die roll: chance of being caught in the act -- player precautions will affect this roll, as will how suspicious the other party-guests are of the character (as determined by the DM above)
(note, check if the lord keeps the keys with him at the ball and snatch it if possible).
die roll: ad-hoc determination depending on the specifics of the situation (is the lord drunk? how friendly has he become to the character? etc.), and the characters' stats and background
After that go to the kitchen, drop the loot into the waste and leave. The next day go through the waste and retrieve the loot.
die roll: chance of being caught in the act, or that someone else discovered the loot -- player precautions and NPC suspicion can affect this roll as above
The only places I can see where a skill system would even really be applicable are preparing the forged document, researching info about the relative and his country, and snatching the keys from the lord, and even in those cases I prefer the looseness of not having a specifically pre-defined skill set because it allows the player more wiggle-room: if you're playing a game where Forgery, Gather Information, and Pick Pockets are defined skills and the character in question doesn't have those skills, then he can't perform those activities (depending on the game system, an untrained character might have a small default chance), but in a more freeform, negotiation-based game, anything can happen. Skill systems in rpgs are inherently limiting, defining what a character
can't do as much or moreso than what he can. In some styles and genres of games that's appropriate (I tend to prefer defined skills in modern or futuristic settings and non-heroic games) but in others it may not be.