Jeff Gawne comments

Unfortunately, this is going to be another situation where the Japanese government finds a solution without knowing the formula. For a prime example, look to the education industry.

And...they just happened to have a can of spray paint with them when they went out drinking. Seems plausible.

Apparently, the Japanese government would prefer all the foreign visitors to hit the department stores or go to the drug stores and fill their suitcases. Wandering through the parks and visiting castles doesn’t fill the coffers.