According to an article in the Malasia Sun, the idea of tourism on the moon is a threat to the historic moonlanding site.
 
The article claims that there are 106 items that the crew of the first moon landing left on the surface when they left in 1969. These range from the legendary flag to urine collection bags.

Of course, what can we do about it?  Make it illegal?  Are the mooncops going to sweep in and get you.  "Hey you, drop that bag of piss NOW!"   The first tourists to actually go there will be very wealthy and they do not have to abide by laws anyway.

Wouldn't it just be easier to ask Neil Armstrong for some piss than to fly all the way to the moon to get it?  I think he lives in Ohio. Hey Neil, would you please piss in a baggy for me to put on Ebay?

Anyway, if someone is going to the moon, you probably shouldn't desecrate the site. However,  if you are going to anyway, please pick me up a Hasselblad Camera or something else cool.