Why not, if the person declear the account as alt, giving a good reason for the one merit. This forum is not against sending merit to alt, but veteran members do not like it due to genuine reasons, but these members can be convinced with good reasons. That is not yet a merit abuse.

What I have noticed is that people that are abusing merit are really abusing it before they are tagged or raised concern about, which means such people would often be sending merit from one alt to another and vice versa, and most especially with accounts full of shitposts. If someone have a good reason to send just one merit from one alt to another and the person is not cheating on with the merit, likely nobody will still tag or raise any concern.