It's not autoban...
OK, this is what I see in the modlog:
Autoban user: N/A in topic #0 by member #782523
...
...
Autoban user: N/A in topic #0 by member #2067403
What it is then?
It just means banned. The log only ever shows as nuked or Autoban, I guess its' a limitation in SMF.
Thanks TheQuin, The message came at the moment I reported them so that's why I thought that they were autobanned. Thanks both of you for the help, and sorry LoyceV for the off-topic.