I do also think so.
He might think that it is very rare to happrn, moreover with that high amount. 3.8BTC is not a small amount, that is a big amount.
However, I also want to ask, there is a tip history and he knows the tip sender, doesn't he? The question is, is there in the platform any chatroom or message to contact each player? It will make easier to find the sender, right?
And if he ask to the CS, I am sire that CS has the data and be able to contact the sender by using chat or even email, I am sure that if contacting their CS, the problem will be solved.
But I am also curious if that is real, not a dream or try to attract all members here by being so honest or even making a short story only. If this exactly true, I really appreciate what he does.

But he failed on getting one as people wont really be that dumb because stories like these are mostly trolling or unbelievable speaking on the amount of bitcoin on that year then it is already big to consider

as a tip unless if his your personal friend or something like that but for a random person? Who would really make out those kind of tips on that big amount?

Mistakes could happen but for someone who do able to do so is impossible on general sense or on any angle.

Which is why it is so weird the OP is bringing this now, after all what do they want to win by posting something like this? I say this because it has passed so much time that even if we assume the event did actually happen the chances of returning the money are very low

Were they trying to gain some points with the community by supposedly being honest about this? Do they wanted some merit? Or was this an elaborate attempt to try to scam someone? It is difficult to know but I do not think the intentions of the OP were as pure as he make them out to be.

The thead should be locked, when their is a misleading points.The tips of casino or gambling sites are mention in the threads can be used by other people. Some tips of yolodice was meantioned here had a unique one. While investing in the crypto currency was different and investing on gambling are different.

It is possible that the username is visible, but the OP did not describe the situation very clearly. We can also understand from it that he cannot access his account and tries to contact the user who sent it to him by creating this thread here.
I also have doubts about the truthfulness of this story, but if it is true, it may be a good thing that the thread will be open and remain visible in the gambling section for some time.