"ip flags are not real. You can argue with me if you want to, but I don't give a shit and I wont reply, take this as useful information if you'd like as I think it's the only thing I will ever post that helps someone with bans."
Unless he works at jagex there is no way to know if they keep checking an IP for a while after they banned an acc on it or not. Or if they do anything else with the ip.
So its obviously just his own opinion. If you want to be sure use pirvate proxys