That is why at a park I usually pack a pair of riding glasses... (The type with an elastic strap, and covers the whole eye, the type for riding motorcycles.) Definately required coaster gear especially at CP during mufflehead season..;) Just throw a pair in your park fanny pack or car, you never know when they are going to be needed, and with the elastic strap I have never been hassled for getting on a ride with them.
--j