I tell you why: Because people are hysterical, and also because it's on private property, so you'd have to ask for permission first. Try something like this: Dear dudes and dudettes from this nipponese power company, I own a geiger-counter and also know the some basics in physics. For example, I know, that one Bq is one decay per second, I know, that my body radiates with something around 4.5 KBq, and I'm also able to perform some basic math. I'd like to test your radioactive water for my youtube-channel, so I can explain to people, how dangerous it really is. So, what ya say? You get some free PR, and I get a shitload of views on my youtube channel. So plz let's make a date, when some dude lets me in, so I can take a sample, hold my geiger-counter in front of it, do some shit for my GoPro camera, and leave.