Alas, THAT is actually a crime, whereas it is highly debatable if the national parks can actually close without violating federal law, or if national parks officials (or rangers) have the legal ability to deem you trespassing on public land for anything other than an actual emergency (forest fire, mudslide, active police investigation or public health hazard.)
So feel free to engage in debate, but don't litter.
If you rip up the ticket and throw it in a trash can you’ll get another ticket for “Unlawful Use of Government Trash Containers”.
Then fire up a Zippo lighter on it.