I'm wondering what other's think about a dilemma we are having amongst BA's in my organization.  When documenting requirements for maintenance to our Legacy system, some BA's feel it is quite acceptable to include current functionality as a requirement if they feel that the enhancement requirements may cause that current functionality to be affected or removed. 

 An example would be something like "Retain current functionality that allows users to update termination date."

I don't necessarily agree with this, though at times it may be valid to express to the development team that the enhancement requirements should not affect current functionality.

Anyone have any comments how to communicate things like this?

 MPS