I never have received a PM as begging merits however once I received a request in PM to review one user post in Bengali thread for merit.
I don't know people still tag merit beggars nowadays but I remembered in the very early months after merit system was kicked off, I saw many neg tags on merit beggars. Anyway, such merit begging behavior is discouraged by forum community.
That's a forum thing and nothing related to trade, I think no one should tag on suh case rather reporting them to the moderators as breaking forum rules "begging".