AFS and changing local UIDs

[nepywoda@fnal.gov]

I have Kerberos and Arla setup on OS 10.2 and I was wondering if it's truly *necessary* 
to change your local UID to your remote "afs" UID. I have setup AFS/Arla on a few 
machines and it's been working without changing the local UID to match the remote 
one. What exactly is the problem that makes it "suggested" to change UIDs? Is it a 
security issue or is it just an issue with the Finder's interaction with AFS?

Thanks,
Paul Nepywoda