That ranger would have been singing a differant tune if you hurt your self day hiking, couldn't hike out, and froze to death on a cold winters night, like this evening. I've never seen an USFS rule that says you can't have a sleeping bag at Deep Creek. I've seen numerous times people who bring down various items for the comfort of laying on during thier day hikes. As far as I'm concerned, I'll always bring on my hikes, what I deem to be prudent to provide for my survival needs, in the event of some unfortunate accident. It could be too, that a prepared person, may find themselves in the position of providing aid to another injured or unprepared person, and possibly even saving thier lives.