Now for an on topic post.... *grin*
I attend 3-4 sessions a week (I know, lucky me!!) and am one of those people who play the most feared and dreaded of instruments- the bodhran- (cringe in fear!!!) Some diety some where decided to bless me, not only with a good sense of rhythm, but with taste and consideration in playing as well... at least that's what I'm told. I just know the session leaders will usually ask me to sit near them, when I'm not otherwise occupied.
We have our share of bad bodhran players at each session. We also have quite a few new folks who show up with a drum, figuring 'anyone can play it'. Between myself, the session leaders and a few of the folks I've gotten to already, we catch these newcomers as soon as possible. I'll usually introduce myself to them, ask about their drum, get some other pertenant info from them and then tell them a bit about myself. Mostly breaking the ice stuff. I'll ask at some point if they have a teacher. Then I let it drop. I'll go on with my playing and let them figure out that I might be a good role model. When then come to me for hint, tips or teaching, I share as much as they will take. If this subtle approach doesn't do it, one of the other session regulars, or leaders, will point me out and flat out say, 'you might want to ask that one for a few pointers'.
This approach has worked for almost every instrument (sorry, haven't figured out how to make it work for bones or spoons :-( ). We also have several 'slow sessions' and learning sessions in the area, some going on at the same time as the traditional session in a different part of the pub. I think having a few people who are willing to share their talent with newcomers, even if it's one on one, can improve everyone's time at a session, while taking some of the onus off the leaders, who have to focus on everyone, not just one person.

And, yes, noodling really ticks me off, as I'm a singer too....

Peace
Starfire