Liz Lee, a new member to the body this year, pointed out that the scope of an organization is ultimately derived from its mission. The following is a passage from our constitution:
The function of the UA shall be to provide an opportunity for its members to discuss and express their views upon any matter which they deem of general University interest and to make recommendations and pass resolutions with respect thereto.This implies that the mission or "function" of the UA is largely subjective. With Liz's statement in mind, as long as a sufficient number of UA representatives feel that an issue is "of general University interest", it is within the scope of the UA to address it.
So now the question becomes, what is "of general University interest?" I'll follow up later but I hope others contribute until then!