If it's not an issue currently, then that's even better 👍
At least on NodeBB we only post to one community, but it'd still happen even if other communities on other instances were mentioned first, so it could still be abused.
E.g. mention four communities on four different instances, get posted to four communities.
L'Italia è un paese talmente fascista che quando si tratta di boicottare la democrazia internazionae, il multeralismo e le organizzazioni umanitarie dell'ONU siamo così stronzi da partecipare al boicottaggio e così vigliacci da esprimere un voto di astensione, mentre l'85% della comunità degli stati vota come farebbero le persone per bene.
So what if Lemmy, Piefed, Mbin, and NodeBB made it so that only the first matching community gets the post?
Not sure about the others, but doesn't Lemmy do that already (only applies the first matching community)? I've been out of the loop for several months, so maybe it changed, but I thought it already did that?