Even if they didn't have the same ip at the same time did u ever switch what account used which proxy having used that proxy with an account already ? If u got banned all at the same time time or didn't post My theory atm is that if u still get chain banned while using proxies then that proxy must have been attached to to another account at some point in time.
Either way based on what jagex has been saying and the results. Boting might be over. Even if your undected now once your flagged and banned the use the same pattern detected from monitoring you to ban the rest of your accounts. That would explain why people using proxies still get banned at the same time even if in remote locations. It makes sense seeing how they are always asking plays to report bots when they see them so they can target bots specific pattern. Even if your script is private once u get banned once you will most likely get banned again and faster. I think is true because i have a private script that at first never got me banned after being banned a couple times i changed things up different route and some other stuff. Afterwards i remained unbanned for awhile again. soon after a couple single bans started coming in and then eventually a massban.