I've never offered any yarn for sale at Rav, but a few folks have approached me about selling some of my yarn. I have done so more than a few times, with no offense taken on my part, and our transactions have been seamless. Win-Win.
Go for it!
Just cuz it isn't listed as 'FOR SALE' doesn't mean they won't sell it...it might be like me: I just didn't think to list it for sale. I'd never have dreamed anyone would contact me.