Been a problem forever. In the 1960s, a camping boom period before reservations were even possible everything was first come, first serve. Redstreak Campground at Raduim Hotsprings had 1oo campers lined up by 10am.
Lake O'Hara, hike in or bus in only takes reservations starting April 1st, They sell out the season in a day.
The guys selling the sites could care less if you are a camper, their job is "Git 'er done" sold out in a day is back slaps all around.
If you open reservations, someone will figure out how to book them all and resell them.
I agree, cancel the reservation system. Make it all first come first served, If you can't handle it, go for a cruise.