They could establish a gulag there and ship prisoners to it. Then have them grow wheat to be sent back to earth. And have a warden run the whole thing with the aid of a sentient computer named 'Mycroft'.
Riiight! And lasers can whistle!
what would constitute "proof", Sparky?
Retroreflection is accomplished by having three mutually perpendicular reflective surfaces forming a hollow corner. Natural cubic crystal formations can easily develop hollow corner retroreflectivity. So, to show that it was the Apollo lunar ranging experiment, and not a natural crystal formation, you'd at least have to have before and after shots showing the difference.
"Experience has proved that some people indeed know everything." -- Russell Baker