I agree that I'd like to see some type of incentive program like Starwood has.

But the above is a separate issue/problem. Marriott has a 'quasi-green' program in place where they don't change the sheets every day on longer stays, but also they have a card stating put your towels here if you're willing to re-use them & there if you want clean ones. But the maids basically grab the towels anyway, regardless if you put them in the willing to re-use spot. Marriott would save some $$ if they'd train the maids to follow the program.

Cheers.