I had a question User Profile Application - MOSS MA not found still outstanding. I believe its a transparent proxy related problem.
The site does not use My Sites, Social Tagging, or the need to sync ad properties back and forth from SharePoint. I'm just use SharePoint groups for the web part targeting rather than audiences as a workaround for that.
The question is, am I setting myself up for future problems, I know SharePoint maintains its own listing of AD accounts separate from the UPSA so provided that exists do I even need the UPSA to be working or can I just leave it there rotting?