I have a sub-250 skill character with 99.5 lockpicking. By the GGS tables, I should raise every 6 hours.... but it seems I only raise once each game day. Also, even with GM chests, I've never gotten a bump out of picking player-made chests. I spent an hour repetitively locking and picking a GM chest set, and not a gain. I pop over to Trinsic Brigand Camp, and get a bump the very first chest I try. Go fig.