So make the containers level acessible... Example: Level 40 + Can open them.
Whilst they may have to now to avoid the exploit, there could theoretically have been an exploration factor in being sneaky or clever enough in getting to a few whilst at lower level. Clearly nobody remembers the thrill of doing stuff when the game wasn't really supposed to let you do it, whether soloing a heroic, or finding a clever way to avoid enemies. Edge gaming, if you like. Seeing where the railroads end. Or maybe that's the tester in me talking
Taking that to exploit levels and actually breaking the game is of course not what I mean; there's a difference between finding an edge for the fun of it and using a game mechanic for inappropriate gain.