Yes, CPR is brutal and more often than not ineffective. That TV trope where someone gets a few compressions suddenly coughs and sits up all alive and healthy again is complete BS. Literally never happens.
My wife's a paramedic and in seven years has only seen someone spontaneously regain pulse after CPR twice - and that's with a team of highly trained professionals and a whole bunch of fancy equipment.
Still worth trying in many cases though, but it's certainly not a miracle procedure and not something that should automatically be done in every case.
Experience, mainly.
I used to run a phpbb forum, on average the bot signups outnumbered the real people 10 or 20 times. And that was with some fairly robust anti spam measures in place - something I think this platform is too new to have properly sorted out yet.
I may be wrong, I don't know how the back end here works, but any place where people can post publicly will be infested with bot signups very quickly. The only real variable is how good the anti spam measures are.