It´s actually the other way around. If we assume that RNG ist just tied to the chest and nothing else, it doesn´t matter if 1 character does the pulling or 1000.
Of course, 50 pulls means nothing, but 1000 should already show decent statistics. Doesn´t matter if one character does 1000 pulls or 100 characters do 10 pulls.
Unless of course, there is some secret hidden per character/account "luck" stat (which I personally don´t believe in). But in that case, any data/statistics is useless anyway.
Early on in this thread,
Aelonwy linked to some experiences she's had with tracking loot between distinct accounts and observed severely differing droprates between them (i.e. she has half the drop rate of her husband's account, her husband's account has half the drop rate of her son's account).
Given my experience in other games with "cursed seeds" (i.e.
Monster Hunter 3U's Cursed Charm Tables),
Asheron's Call's Wi Flag, and the statistically improbable strings of loot and no loot people have reported earlier in the thread, and my own experience with "bad" dice RNG (i.e. UMD dice rolls resulting in the exactly same number 6 to 8 times in a row, repeatedly), I wouldn't be surprised to learn that:
1) The RNG in this game is set up in a way that causes observable "streakiness" (i.e. part of the seed generation is based on instance ID, the current timestamp fed into a sin function to constrain possible results, and is only updated every X time units to save on resource utilization).
2) That the algorithm responsible for loot generation has the same flaws that caused the Wi Flag (dynamically generating a list based on inverse ratios that creates a range larger than the RNG is allowed to roll, causing a truncation of the possible rewards).
Given my play habits, I'm regularly ransacking chests across multiple characters on elite and r1. My results overall, converge towards 33% (I'm not performing rigorous testing and stop farming after the item I want drops), but I have anecdotally observed that there are times that are distinctly not for farming (i.e. 8 to 12+ consecutive pulls without any named items) and conversely times for farming (i.e. 8 to 12+ pulls with an item every time). When things are "not good for farming", I do something else (sandwich, nap, other games, housework, whatever) for a while and I believe this habit of mine causes my results to skew higher than expected (again, my sample methodology is not rigorous). I haven't figured out how to automate my data collection yet (I've got a couple ideas), and ultimately I'd rather spend my time playing the game (but who doesn't love a good mystery to poke at).
There's also the story about CITW
back during its release that I found super interesting to read. I do remember getting any of the loot from that raid back in the day was a massive pain because nothing was dropping but I certainly wasn't recording the number of runs (just when I rolled well on a Mornh, I immediately TR'd into a (bad) drow hammer paladin to use it). Maybe when DDO finally dies, the source will leak and I'll be able to poke around until I'm satisfied.