It's not everyday that you get tot receive 1 eth to your wallet and there could be a reason since this is no small amount will try to trace the owner and thank him for sending it to me, and if he says he wants it back and was sent by mistake I will just send the half this is to teach him a lesson that he must always check the address and for the time and effort I spent looking for him.
LOL, what if he wanted it to sent to you in full because he will going to use it for medications. Are you still going to send the half of it?
In my case I will negotiate with the one to teach him a lesson to double check first before going into transaction. If he has no good reason for him to get back the eth to him then i will send 80% only and 20% is to teach him a lesson. This I think the better way than having it 50% which is relatively high and of course due to pandemic we all need finances but this could not be the reason to own money mistakenly sent by you.