The last banwaves have been due to detection of HonorBuddy, so no matter what you had done, if HonorBuddy was attached to a WoW client, that WoW account was suspended for 6/18 months.
Bossland and his crew are doing everthing they can to prevent Blizzards detection service but it only take Blizzard one successfull attempt to breach the anti detection software and everyone that is botting at that moment will be suspended.
So is botting safe, no it isn't (or yes it is, depending on how you look at it), sooner or later you will get caught (unless you're extremly lucky and are not botting the times that Blizzard manages to get past the anti detection software), don't bot on accounts you don't want to loose.
But that is talking about banwaves, then Blizzard allso ban accounts here and there due to player reports, repetable pathings and such, those usually end up in a permanent ban and not suspension and are not caused by detection of the software but other mesures.