It's a third party software, ofc you can be banned for using it.
Copy pasta from rs.com I'll bold the important part for you
These are some examples of third party software we ask you not to use:
Software that attempts to communicate directly with our game worlds.
Software that monitors, modifies or decrypts the communications between our game applets and our game worlds.
Software that generates input to our game applets. This includes software that automatically moves the mouse pointer or generates mouse clicks or key presses.
Modified or replacement versions of our game applets. Reverse-engineering our game applets is strictly prohibited. Using a modified version of our game applets is not permitted for any reason. Third-party software that displays pages/content from our website(s), and that has specific features (i.e. toolkits) must not be used to access our website unless that software conforms with all of the other rules, and the following additional rules:
It must not encourage rule-breaking or endanger users.
It must not contain adverts or links to websites that encourage rule-breaking or endanger users.
It must not automatically make repeated page/content requests from our website or otherwise make excessively bandwidth-intensive requests from our servers (each page/content request should only be in direct response to a user request each time).
It must not bypass the normal navigation of our website for users wishing to reach the game worlds. The software should initially only point at the front page of our websites, and should require the user to navigate through the website normally to reach the game worlds. The software must not contain or acquire direct links to the game applet.
It must not hide or encourage the hiding of any of the adverts on our website. To avoid encouraging users to hide the advert above the game, the pane displaying pages from our website must default to at least 630 pixels high (if viewed on a screen with a resolution higher than 800x600), and it must not be possible to resize it to less height than that, i.e. the page must be displayed in such a way that both the game and advert are fully visible at the same time.
It must not attempt to make it easier to enter a busy game world than it would be for users not using the software. It must not contain any features to make it easier to enter or monitor busy worlds.
If the software has its own integrated chat feature, separate from the game chat, it should make it very clear to users that this chat is not part of our games and is not official, endorsed, or moderated by Jagex in any way. Furthermore, this chat should still be moderated (just not by us), and the moderators should not allow chat which infringes our Rules of Conduct. To avoid confusion with the official game chat, moderators of the external chat should not be indicated with a silver or gold crown. If the chat is IRC based, then the software should only allow access to IRC channels which conform with the above rules.