You'll need that 5%
to pay for the class-action law suit brought by those irate people whose car's have been pooped on by birds, windshields smeared by sap, or covered in leaves/seeds/fruit.
Just because you rabid environmentalists want to see a few trees instead of luvverly asphalt, you'll be lining the pockets of those @&$%%@# trial lawyers.
Cheers,
Tony
P.S. Apologies to all concerned ;-)