We limit rental of the facility to corporate members at the $250
or higher level, and to individual members at the $100  or higher
level.  Thus we regard rental of the facility as a benefit of membership
along with free admission to exhibits.  As such we feel there is
a valid argument that such rental income is not unrelated.  So far,
this hasn't been a problem, as we really haven't found our market
niche and so there hasn't been much income.