I ran a website for youngsters several years ago. One of the duties to maintain it was to moderate discussion boards. Some kids were difficult to manage and would not accept to be banned (via email/IP/or whatever solution) and would keep recreating profiles. Ultimately I dealt with those ppl by “greylisting” them. Added a sleep() prior each page rendering of 5 to 25 secs (actually it was more sophisticated and would…
I can even imagine it tamping down "reply wars" and long arguments since you get more decompression time between impressions.