In the past, when we changed a PerfID in order to consolidate two performer entries, the original page would 404 out, since the perfid was no longer in the db.
We’ve had a table that kept track of these changes — Peter and I would keep them up to date with our changes, so we would stay in sync — and we’re not consulting that table before giving up on the performer.
This will stop bookmarks and incoming links (I’m looking at you, Google) from breaking. We hope you find it marginally useful — we’d hate to think we spent those 20 minutes foolishly. :-)