Is this a real thing? In my current Pathfinder game the Paladin is the best character at picking locks. Even in 1e we had non thief character pick locks.
Must have been a house rule you were using in 1E.
In 1E, only thieves had the thief function table (pick pockets, open locks, find/remove traps, etc.). So, only a thief or a multiclass thief.
In 2E, only rogues and multiclass Rogues, and the multiclass rogue couldn't do it in non-Rogue armors. Bards could pick pockets, but not locks or traps.
3E introduced class skills and skill points, so if these were a cross class skill, then it was half skill total max. And like in 5E, you could not pick locks untrained (although you could bust them open with brute force), same with disarm traps.
Granted, there were probably some splat books in some of these editions that expanded it a bit for some classes or added classes that could, especially in 3E. There might also have been feat(s) in 3E that allowed one class to pick up a cross class skill as a class skill, but I don't remember one.
I don't know about Pathfinder. I only played it a few times.