I'm a utility cyclist. Usually when I ride, I wear good outdoor shoes that are waterproof and hard-wearing, so it's OK if they get scuffed on pedals or splashed with mud or oil from the road surface. (Proper mudguards help a lot but still aren't 100% effective.)
On occasion, I go to an event in formal dress, which entails wearing black, polished leather shoes. It's a lot harder to keep these clean and shiny. If I've a long ride to get there, I'll usually wear some shoes that are better for cycling and keep my black pair in my bag. But if I'm only riding 10 minutes to get to an event in town, having to pack a second pair and change them is a lot less convenient.
Is there an easier alternative? A plastic bag over the shoes, secured with elastic, would keep them clean, but not (I fear) protect them from scuffs; besides, I'd be afraid of slipping when I put my foot down. Any other ideas?