Nice discussion,
Yep, parameters or items in drawing notes do get updated when Session ID of the referenced component changes, but the problem is that for instance the text/code of assembly relations doesn't get updated when that happens.
If you consider an assembly to be a parent of some parameter values inside parts of this said assembly, then such sudden change in Session IDs can lead to an unexplainable yellow light on every regen. It just won't be treated the same in the list of failed items, it may not even show you the right component that has the relations set wrong all of the sudden.
From time to time I use Session IDs to create temporary relationships between assembly relations and it's parts relations, that is when the relatioships just can't be created with geometry only. After all is done and when the result is good enough I just remove such relationships.
Question is can you automate the creation of such relations, and also it's removal? Well, then Session IDs is something for you that you may end up using extensivelly.
But if you just want to define relatioships, and keep the definitions in place then have a look elsewhere. Alot of relatioships can be defined just with geometry on model level, and system params on drawing level.
http://odin.me.memphis.edu/ptc/usascii/proe/detail/system_parameters_for_drawings.htm
