[Roshie5u]

It is true for checking final solution, but what in case of partial results? I am not sure about monero but with BTC I could claim I checked range assigned to me and found no solutions. I guess mining pools have solved it in some way.

edit: I see that Coinhive pays only for solved hashes, so there is no way to "harm" them, and for website owner it makes no difference if hashes are not computed at all or invalid results are submitted.