1) Do all the 170s used on this route actually have CCTV fitted? I am fairly confident that all the refurbished units will, but I am not so sure about the ones in original condition.
2) If the unit has CCTV, it is all very well the Police being able to see which person is doing what, but they do not neccesarily know who each person is, and in cases such as this it must be very difficult for the plod to track down the culprits. This is where Sulzer25's evidence could be useful.
As for me, I am a Hull City supporter, I travel accross the country every week by train, I am tee-total and I am not a hooligan. Indeed, I manage to combine my hobbies quite well.