Did you notice the time of the post was was the same?

About a dozen, replying to other posts subject line, all in the same minute.

This has been happening lately on another one of my hubs, and I ban them immediately, but these idiots come back, and are pros at creating new IP's.

Until Agora finds a fix, such as your excellent suggestion, us members/HL's need to pull the trigger.

I reported 1 of this guys posts as a spam violation, asking for a banning.

Good idea on your part, and in fact, a new member has limited posting of I think 10 per day, and even fewer PM's. Maybe that should be 2.