Lance's next nike commercial:

"We can work together to find a cure for cancer. And, be sure not to litter!"

Seriously OP, you're worrying about something completely negligible. Until I opened this thread, I never even thought about what happens to the riders' trash.

If this is truly important to you, start a NPO who's mission is to "clean up the peleton" or fly yourself over to France and follow the tour around with a bag and a pointy stick.