In case you were wondering, attorney Kenny Ching at GOOD says painting guerrilla bike lanes on your favorite cycling streets is a trouble-ridden idea. What kind of trouble?

Catastrophic trouble. Never mind property damage and vandalism. You could be responsible—legally, financially, and otherwise—for a car hitting one of your fellow cyclists. You’d likely be found negligent because you should have known (a reasonable person would have) that by painting a bike lane in the street that didn’t really belong there, people would ride their bikes in it. You should have also known, because a reasonable person would have, that cars that regularly drive on that road wouldn’t be expecting bikes cruising down the middle of it as if they owned it. Finally, you should have known that, at some point, this would cause some car to collide with some bike. At that point, because of your breach of your legal duty to act reasonably, you will have caused and be liable for whatever damage occurs. You’ll be extremely lucky if it’s only a wrecked bike or car.

If you want to get a bike lane, do it the right way. Go to your city council and ask to have it made official. If you want to dramatically increase your chances of getting this done, get a bunch of your friends and neighbors to chip in, go to a good law firm, and hire a government affairs attorney who specializes in local government matters. She might even do it pro bono.

Or go straight to unlikely bike champion Ray LaHood. For subversive fun, guerilla gardening is a safer bet. Although, says GOOD’s Ask a Lawyer feature, seed-bombing has legal risks too.