Why is this so funny to me?

We were volunteer camp hosts at a Forest Service campground that had "day use." There was a small lake with a beach and fishing pier. The fee was $2 per person to enter for a day. There was also the campground with separate camping loops. The other four or five campgrounds in the same National Forest did not have any "day use" areas - only campers were allowed in the campground area. Spelling aside, the sign makes more sense than you think.

Rob