If, as you are saying, that some certain park(s) have a "required form to fill out", then that information/requirement HAS TO BE THERE somewhere. In writing (codified), as a requirement. Because There is simply no laws or rules that are "secret". Otherwise that's "ex post facto" (in legal jargon), eh ?
Are you referring to something involving "alter & deface" (that someone needs a permit form to "dig" ?), or "harvest & remove" (since you and I "take" things). Or lost & found laws (since we "find" things after all). Yet in all those cases doesn't specifically mention md'ing ? But such that someone has allegedly decided that our activity falls under some *ancillary* language ?
In other words, can you please clarify.
Because whatever "form" you are speaking of to-fill-out ^^ HAS to be listed SOMEWHERE. Because you and I can not get in trouble for doing something for-which-there was no where to look up. So: Can you please clarify ? Got a link ? Got a pix of this "form" that you're referring to ?