We simply cant do that by all ourselves. Scam ICO's should be recognised individually and must be warned to everyone on the forum before they catch others and scam them.
You can only get awareness about it this way but you cant simply ban the ICO's or hunt the scam ICO's and close them. Remember we are on the decentralised stage and here everything is ran over the public knots and we can not stop anything here as long as it comes under some jurisdiction etc. If there had been any way then I am sure we would have ended up closing almost 90% of the ICO's. lol