It all comes down to who owns the balcony. If the balconies are limited common areas, condo owners have to abide by the rules the association sets, as long as the hoa is within it's mandate. If on the other hand the owners own the balconies, it's a different situation.
We should be applying the same common sense approach to a lot of things, like weed, meth, coke, gambling, sex, etc.. If it's an individual decision, occurs on private property, and doesn't unwillingly effect someone else, it shouldn't be restricted by governing bodies.