Self-amalgamating tape sounds quite good, but am I really the only one who thinks sticking something black over a light or bright-coloured frame is a f'n ugly solution? Kind of protecting the frame, but only by never being able to see it at its best.
Anyway, I use a few layers of transparent waterproof tape. Renew it every now and again, doesn't seem to damage the paint, and you can still see the colour.