Delimicus is wrong, and Blizzard is lying. I’m currently suspended with no GM interaction, and the reason was abusive chat.
Shortly before this suspension, I was kicked from a WSG game while I was crossing mid and given a deserter debuff. I asked why in public chat and people said the obvious, that I was reported AFK. I actually went AFK while I was waiting for the debuff to expire, and when I returned to PC I was logged out due to suspension.
I’ve had dozens of chat suspensions that weren’t overturned due to “abusive chat” (read: toxic server that I trolled too much) with the longest ever totalling 256 days. This was entirely without GM interaction. This is the first time I’ve actually had an account suspension though, the previous ones were always just squelches from using any chat.