This thread might be better placed in "Systems"
Anyways...
Despite have a character who specializes in stealth, I can say I've only ever gotten Rouge XP a handful times. I believe there need to be a very real chance of failure for it to give you anything. If anyone happens to the the details behind the system it would make a good article for the wiki.
Maybe there's a way the threshold could be expanded slightly without opening it up to abuse? I feel that if people are questioning a mechanics existence all together it might be a bit too stringent.
That's exactly my point: I sneaked past enemies for a long time. Enemies far beyond my CR. In the third run I was scouting I was spotted. And killed.
Thus:
1) I was sneaking.
2) The CR was high.
3) There was a risk of being spotted (I even was).
4) I gained no XP.
So, the system as it is doesn't seem to provide a way to gain XP other than hacking your way through a dungeon, giving other roles to a PC specialize, the primarily function of this system.
I'd question even the "risk of being spotted factor" since battle designed PC's gain XP from creatures they surely won't die fighting. Thus if a level 8 Fighter or Cleric PC is able to go toe to toe with skeletal warriors and gain XP safely, why a rogue designed to sneak have to risk too much more to gain some XP?
I'm just questioning the fact that to me I've never see this system working and if this was created there must be a good reason that, to me, it is not accomplishing.