Any time I'm reading a new RPG and come to the section on skills, the one question that always comes up at some point is "But how does it want to handle the whole party sneaking past guards together?"
The most simple approach is that every PC makes a skill check to avoid being seen by all of the guards, and that every guard makes a skill check to notice any one of the PCs. If only one of the guards manages to roll better than only one of PCs, the whole thing is up and the players are discovered.
And when you have four to six PCs and four to six guards, even the PCs are all much better at sneaking than the guards are at noticing, it becomes statistically very rare for the players to ever get past guards unnoticed.
What other approaches to handling such a situation with skill checks have you come across or come up with that makes sneaking past guards with the whole party a more feasible option for the players with a decent chance for success?
I haven't used this but while reading the comments it came to mind: what about using something like a 4e skill challenge? Say they need a number of successes before a number of failures (maybe successes is determined by the number of sneakers and failures is determined by the number of watchers somehow, or the skill of the best watcher). Then it's up to the players to justify how they assist in scoring successes. Sneaking, disguising, distracting, etc.