About one quarter of the paper I picked up while working in the parks had either a credit card number on it or a name. Be smart and leave your parks clean. Most people know the basic rule of camping. Leave your site cleaner than you found it. Camping fees have gotten out of hand in many places - but I assure you that the employees who will clean your campsite are not benefiting from these cost increases.
Many people seem to think that leaving the campsite a mess is a fair trade for the camping fees.