Hey buddy, I know how their system works. Nearly all detection is done automatically. Every account logged in game at any given point is being analyzed by botwatch. Certain actions can cause you to be automatically banned, meaning there was zero manual intervention, but those aren't too common compared to everything else. Most bots are analyzed by the system and when the system is confident enough that the account is botting, it'll be flagged and added to a list. This is where the "manual" work comes in, and all that is is a Jmod quickly looking at whatever data it is they look at and confirming it is a bot before issuing the ban and this is done because their bot detection system isn't accurate enough to allow it to dish out bans 100% of the time by itself.
Your interpretation of "manual reviews" is a jmod sitting down at his desk and individually looking over accounts 1 by 1 trying to determine if they are a bot. This is NOT how it works over at jagex and anyone who thinks that someone is there looking over 10s of thousands of accounts 1 by 1 trying to nitpick bots is braindead.