There aren't any plans on adding bans on myTeamSpeak accounts. Anyone who does circumvent bans today, is determined enough to do the simple extra step of logging out as well, so it is of doubtful usefulness at best.
As for an API it would need to be discussed, but currently there aren't any plans for that at this point in time. It's a very new service and for now we're focused on improving the existing platform and add new features to it.
An API is also always kind of a double edged sword and can be abused for malicious intends. If there is ever going to be one, then it will most likely be some time (ie. not this year).
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