Do you want to say that the person who received that money may have spent/withdrew it from CEX and that this could be a problem in the event that customer support contacts him and informs him that it would be desirable to return what obviously does not belong to him? That might even make sense, because there might be some new complications for all involved parties, and CEX in this way (by doing nothing) is actually letting everything go into oblivion, even though it would be ethical for them to try to resolve this situation between two clients.
It is even possible that the person who received the coins by mistake wants to do the right thing, but also fails to find out to whom the coins should be returned.
I completely agree with you that if the CEX and their support staffs show some kind of actual intention of support for the user in trouble, it is better for their exchange brand.
I guess you understand my post well enough but let me explain more. If that user used the mistakenly sent money for things like Margin tradings, Futures trading and already lost most or all of that money, it is now impossible to return it.
I don't know in case if it is brought to the court, will that person has to refund it to zazarb. It can be order by the court but if the person was already bankrupted, no way to get any sort of refund, big or small, all or part of initial fund.