IMO, Blizzards uses player's reports and some kind of detection on its servers, so you can be detected when you are playing with the bot, if this is not safe or overload the server as HC did. Of course, always exist a chance to be banned. Also, Blizzard doesn't ban a unique player (except that you put a video of the bot on youtube or similar) and does ban waves. Maybe last one was 16-Jan-2015 but I don't know it was real or no because I didn't see ppl banned.