I remember when playing vanilla these chests were left for those who could open them. Rogues and/or someone with keys would keep them or roll among them.
I don’t know if it was a thing that changed by server, like some kind of local rule.
I was in a dungeon not too long ago and the party reacted angrily when I looted a locked chest. True, I forgot to ask if someone had keys, but honestly, how many do carry them? I unlocked the chest, waited a bit to make sure no one argued against it after I said it was a rogue chest, then picked the (awful) content. We played a bit more and after a while the group started complaining with me and another one pointing out it has been like this in vanilla too.
Now, I don’t wanna be seen as a ninja or something, what I did was just what I’ve done back then and no one complained about.
Without starting an argument as to why a rogue/keyholder should or should not keep the content I just wanna make sure as to what the common rule for the server is, to avoid arguing with people over a valueless green item.
Also note that after the group got heated I offered to roll for the chest and my number turned out to be way higher than theirs. Which got me kicked.
I can either assume that either they were honest in their belief or since they kicked me after I rolled higher than them they were salty they didn’t get to keep the loot.
There’s no general code about it, I’m fairly certain. Last time I had a rogue in the group he opened the chest and we rolled for it. I feel that’s fair - yes, we wouldn’t be able to open the chest anyway, without the rogues help, but we still helped the rogue get to the chest. Without us he wouldn’t be able to open it either. It was fought for as a team, so it should be rolled for as a team. Lockpicking is one of the perks a rogue brings to the party, just like my totems, a mages water or a warlocks soulstone.
That said, your group didn’t really handle it all that well, the way you describe it. If they didn’t like the way that played out, they should’ve said something earlier. Generally this is a communication thing. Talk to your groups about how they wanna handle things.
Personally, I open them, post the green items inside and then step away from the chest. Often, people are already rolling for the chest in advance.
There is no one-size-fits-all rule IMO. Best to just ask away and communicate. On the rare occasion where I needed something in the chest, people tended to be forthcoming and give it to/leave it for me after asking.
Raindancer:
Yes I see where you’re coming from, thanks for posting. I didn’t mean to start a debate as to why rogue should or shouldn’t keep the content but since you brought up why you think they shouldn’t, I’ll bring up that totems and water are not nearly as annoying to skill up as lockpicking, which is a bit of a tedious job, that plus herbs and ores are not really rolled for, unless multiple characters can harvest them.
But I’ll just talk with every group I’m in from now on, it was the first time I found a locked chest playing classic with random people so it came as a “cultural shock” to me.
Sice:
I’ll probably do that too and ask to keep the things useful to a rogue like fadeleaf and swift thistle, which I noticed are sometimes in locked chests.
EDIT:
Also in their defense, while the group handled it poorly so did I. I could’ve done it better too, not just them.
Someone clearly didn’t do the water totem quest chain 
I get it though, I had a rogue myself roughly a decade ago and spent a long time leveling lockpicking. But I’d still say that lockpicking is one of perks the rogue brings to the party. It might be an annoying perk to level, but still. Chests are aquired as a team, so they should be rolled for as a team. The main difference to ores and herbs there, I feel, is that the latter are vastly more common outside of the dungeon (unless you’re running BRD for dark iron ore, I guess). It’s also usually not needed by the people who don’t have the ability to loot it.
That said, your opinion on the issue there is just as valid as mine, not trying to convince you that you’re wrong. I’d still say the fault in your particular case lies with the group for not communicating clearly that they wanted to roll for the chest.
/edit: Just saw your edit. That’s fair. I guess a general communication issue on both fronts, then 
Yeah sounds like just an opinion kinda thing where no one is really right but it’s up to preference. What bothers me the most about the whole thing is the misunderstanding and having bad blood with people. I like the social aspect of classic and having people who dislike me just for a messed up communication sucks.
Maybe give it a day or two to cool, then message them one by one to apologize and have a conversation about it.
If I can find the names again I’ll try, I’m a very shy person so it’s gonna be a difficult task though.
Could try letters, if that’s easier
Welp. I was planning to send them some cooked sagefish since they were all mana users as a peace offering, don’t have their names in the chat anymore 
Lockpicking is the rogue’s utility, like a mage’s portal and water or the Warlock’s Soulstone. It’s a group thing.
I always unlock chests/lockboxes for group members, and we roll for all chests. Its not like its difficult to level the skill. I have spent at most two hours dedicated to levelling it. You can do a lot of it along the way as you level with junkboxes too.
Speaking of Junkboxes - They also contain blinding powder later on. That’s useful to know, when your rogue toon isn’t a herbalist
Also: Pickpocket can be macro’d. So you can steal while you hit them!
Quixzy:
I already made up my mind about how I’ll handle it next time so this isn’t to argue and try to change things in my favor, just explaining how I see things.
But a soulstone brings an advantage to the group when it comes to progress, so does water and food from a mage.
The content of a chest doesn’t help the group, and the way I see it it’s like mining, herbalysm and skinning, you can do it, you keep the loot, I don’t ask those with professions to roll.
I’m still gonna accept that the majority now seem to see it differently compared to how we did in my server back when I started and roll for the chest.
I haven’t even learned the recipe for blinding powder, to be honest. So much blinding and flash powder comes out of those things, I never have to worry about my supply of it.