I've heard a few times though that this group of traders are an elite group and tend to only want high-end trades or trades for more rare pins. I have no experience personally but from what I've read they can be rude and definitely are for more experienced traders.
And yeah, I just ask each store if they have pintrading. I've seen a couple of
youtube videos that show numerous stores are doing it so hopefully you have fun and get some good trades. I'm going in 9 days and will be pintrading so I can try to update later