I'm currently attempting to get more information on this. I can tell you however that the "spamming zt" requires a VERY large number of emails to be sent out in a relatively short period of time. From memory, I believe the regular "spamming" comes up when you go past 100 within 1 hour, but the ZT I believe is added when you go past 1,000 by a significant margin.
I'm still investigating this, however I can tell you that it more than likely will be considered a permanent suspension that cannot be removed. I'm still looking to see for sure, however.