Those were not “bans” specifically. A ban actually is permanent. There is no such thing as an automatic ban, all reports are reviewed, and any penalties are handed down by actual GM staff.
There is a squelch system, primarily to help quell gold spam, but all reports that actually lead to a silence, are also handed down by actual GM staff, after reviewing the reports in the system.
Even bot bans, which can be programmed and tracked into the anti cheat programming with in Blizzard’s game, are all reviewed by actual people to ensure proper handling.
That does not mean that mistakes do not happen, and that is what the review process is for.