Well yes, that would be a breach of contract..
An interesting question is, while OG held the coins, did the forum own those coins, or just owned a contract?
I'm not sure.. What do you think?
I often look at it as, if you don't own the keys, all you own is a contract..
I think if we go the "code is law" route then it should have been multisig. Then claiming airdrops would not have been possible without explicit agreement, or at all.
Instead this was a fiat-like escrow/loan/whatchamacallit ("[...] the treasurer owes the Forum the held bitcoins [...]") and I do believe that the forum had more rights to the funds, not merely a contract.
Then there is the question of ethics. Regardless of how the contract is interpreted, in my opinion the ethical thing to do would be to pay all claimed airdrops to the forum, minus a reasonable fee for the effort. This is not so much about the specific instances (I know some here could argue to death that 7 BTC is dust compared to the 500 returned BTC) but about the general interpretation of unforeseen events for the benefit of the customer. Where is the threshold for that to start to matter e.g. in OgNasty's escrow service.
Did the contract even specify which Bitcoin fork would be the real Bitcoin? I don't think it said anything about the longest chain or most POW or anything of the sort. What if theymos and Og had different opinions about that and asked you to arbitrate. What would you say?
It's not like they seek permission from you about how they use that wealth.
LOL, you should really read the 5 pages of small print that you sign when you open an account. Granted you're giving them the rights to everything including your firstborn but that's not the same as saying they can do anything they want without asking.