It always puzzles me, how restrictions of such kind always match economic interests of some service providers. For example, in Hawaii the park rangers now look for any excuse to block your access to Mauna Kea. You need a 4WD, and if you have a 4WD you need more than half tank of gas, and if you have both you can't take children under 12, and so on. But if you buy a tour ($280) somehow children under 12 do not matter, they'll take anyone. Same here. You can't go, but hire a guide and suddenly you can.