Because I have manual control of my TVs inputs, I can force SCART to be RGB or S-Video etc Seeing as your TV auto-detects the RGB signal and switches to the AV channel, cutting wires will lose you this functionality and probably place the TV in composite. If you can get yourself another SCART cable, nothing fancy, just one which can be easily opened up then you have something to compare and test with.
I get the impression that like me, you have more than one RGB SCART device. Consider this great bit of kit from Joytech, which I use to connect my four consoles up to my single RGB SCART input.
Joytech AV Control CenterBefore I had this, I had a cheap 5-way SCART splitter block. The input sockets all run in series, with an output on the end. The input closest to the output had the best picture and each socket back had progressively worse picture quality.
SCART is definitely not made to be plugged in and out all the time, a worn socket can be a nightmare, when the connector keeps dropping out.