Is using the "spam bug" bannable?

{quoted}

Title ^

I have no idea what bug you're talking about, but usually abusing bugs is punishable. Abusing gameplay bugs will normally get you immediately banned, and if you're abusing a non gameplay bug to spam other players that would be considered to be intentionally spamming them, which isn't really a recommended course of action and can result in punishment.

It's basically a bug/exploit that happens when you press a letter and the enter key at the same time.

No that isn't a bug or an exploit and that has existed since the beginning of time within online gaming communities.