I've always found that a rubberband around my cuff would suffice.
Sounds like an answer to a non-problem.

@papizar: I use a reflective strap to tie down my cuff. But that still doesn't prevent bike-grease from getting on my trousers.

Also, a belt will also last 3 times as long as a chain and require zero maintenance or lubrication. A belt also allows one to do away with the deraileur, the part of my bike that I whack out of true the most as an urban/commute biker.

To me, those are tangible improvements over a chain.

If you take a bike on public transit, having a belt-drive rather than a chain makes a difference. A rubber band around one's pants cuff does nothing to prevent the greasy smear on one's shoulder from hoisting the bike up to carry it downstairs into the BART station.

Your points are well taken.