This was from a May, 2000 archive so "last year" is 1999, and 6 months of it would have to encompass some, if not all, of our date range.I played UO last year for about 6 months, one of my characters is a "pure" dungeon rogue - he does not fight. He is near GM in hiding, stealth, lockpicking, detect hidden, etc. He has 96.9 lockpicking currently, and there is no chest he cannot open on the first try. because he never breaks a lockpick, he uses a set of "newbie" lockpicks that rez with him.
I assume he is speaking of level 4 chests and below, since he's talking about dunegons and not t-maps.
I don't know what to make of this quote. On the one hand, if he has 96.9 lockpicking and has 100% chance of success in opening chests, he shouldn't gain skill anymore from those chests. So he's either not trying level 4 chests, or he is trying level 4 chests and is simply not going to gain any skill unless he does level 5 chests.
In any case, the "not breaking lockpicks" thing seems like a reliable bit of info. I think newbies get 5, and on UOSA you'd go through them pretty quickly even at 100.0 lockpicking.
As for the success rate, that's a whole other issue. It is quite possible that you could not fail to open, nor could you gain skill on, level 4 chests at 96.9 skill. My guess is that you'd then need to raise Detect Hidden to some amount so you could attempt level 5 t-map chests and have some chance of success (and thus some chance to gain), and then once you got to GM lockpicking, you could drop Detect back down if you want.