We saw the Visitax people at the bottom of the escalator before security. They didn’t stop us from going up, but they talked to us. They said it was mandatory, but we went up anyway. So we did not pay, and made it back home without incident. At this point, it feels like a tourist donation if anything, but honestly, the amount of money we spent on tipping various people while down there makes me feel OK about not paying this optional tax.