I don't own a fixed-gear bike and I have never ridden one .... I have, however, gone on youtube and watched video of folks riding fixies. Very interesting the way the hardcore, "I've got no brakes but can pedal backwards" fixie rider stops ... the rider leans waaaayyyy foward, down on the handlebars and top tube, locking their legs and sliding to a stop.

I think if this was my idea of fun, I would certainly invest in a pad for the top tube .... probably the stem, too ... and it wouldn't be paint I was thinking about.