It's because when you run Runescape, it installs some dlls that detect when you are and are not using the official client.
They're doing it under the radar, but check your RS folder. You can find them.
The client was detected by Fagex, so now any account that you run through the RSBot-6018 client will get banned within the hour. The developers are working on a new client but it might take a few days because they'll have to remake it from scratch.
@Raple please rename my RSBot-6018 to Detected.
It's because when you run Runescape, it installs some dlls that detect when you are and are not using the official client.
They're doing it under the radar, but check your RS folder. You can find them.