Session IDs in the URL

Possibly in the index

[Tonearm]

My site suppresses all session IDs from appearing in the URL if a robot user agent is detected, but I'm concerned that some may have slipped through anyway.

I have somewhere around 500-600 legitimate pages. Google reports about 600, but when I start browsing the pagination it drops to about 450, so those are the only URLs I can inspect. A session ID doesn't appear in any of those 450, but what about the other 150?

Yahoo Site Explorer reports about 1200 pages of which about half are duplicated with a session ID. Those duplicated URLs must be very old because I'm sure the site is properly suppressing session IDs at this point.

How would you handle this?

[Tonearm]

I did a few searches and haven't found any references yet. The Yahoo Inlinks search isn't 100% either?