Park Rangers - aka game wardens - are stewards of the land (& resources - plants, animals, minerals) they protect. Please correct me if I'm wrong, but I'm fairly certain PR's are given slightly greater powers re: searches - as it's their job to protect from poaching.
Coupled with the current economy, I'm just guessing that bringing in a few more dollars due to incurred fines (speeding, alcohol possession, etc) will help ensure their occupational futures. Sounds a bit Orwellian, don't it
It's ALL Bush's fault.