Having said this, I have absolutely no aversion to anonymising the data. It certainly appears that it will need to be done for places where there is fear of litigation or court orders forcing you to reveal that data. I just want to make sure we dont lose big chunks of functionality in doing so. Cool. Thanks -- I know it is an ethics area for ALA members, and possibly a legal one for Euro, etc librarians.
In talking things over with people. Perhaps having a last borrower record attached to each item then demographically anonymising the issues data on return might be the way to go? Sounds cool to me. Another reason to do it is for weed out candidate lists (you know, what isn't being used at all).
Or even worse someone returns a dvd case without the dvd in it, the data is anonymised, now someone has a free dvd. Perhaps. Don't we have (or shouldn't we have?) a function that returns permits "who has this now" checks on a barcode. Most library circulation staff (with perishable items :) like DVDs, etc) open the box/case before running it through the return function -- a "who has" would let them check w/out removing the item.