The comment:
In a similar vein, it would be interesting to know if going around the moon rather than to the ISS removes any legal hurdles. Do we have any questions covering the legal ramifications (if any) of breaching the ISS's Keep Out Sphere for instance?
under the question Does SpaceX have any significant additional legal hurdles for flying private citizens around the moon? has inspired me to ask What is the "ISS's Keep Out Sphere" and what is its radius?
I have found some references in this blog but I am not sure I understand it completely.