This is a real problem for art galleries and museums since the issue of the saf
ety of the art should always be at the top of the priority list.  Often outside
 organizations wish to use museums/galleries for receptions since they offer la
rge spaces which are attractive and "high class".  Galleries and museums are
 tempted to rent out space to raise money.  Or even to use it for fund raising
 internally.  It is therefore important to have a firm policy in place rather
than try to respond to each request--political powers being what they are.
Alcohol is always an issue and raises the danger level, especially if the
 reception goes on.  Restricting WHERE an event can take place is important.
Also WHO is eligible to apply (for example, using Friends  membership of a
 certain level as incentive).  Be sure to build in guard, receptionist costs.
There is no easy solution or policy which will work for every institution.
We struggle all the time.  Good luck!