|Sounds like you have a pretty good system going for you. In our line of work, a little extra care never hurts. (Like Lee/AR, I also keep a file with all my E&O policies since my first commission. It's easy because I've almost always bought four years at a time, coinciding with each commission.|
As for stamps, 'crazy' California requires us to destroy our stamps once they're no longer in use, but they also issue a new commission number every time we renew. So we're required to have different stamps - with the expiration date printed on it - which could make the situation you described at least a little more difficult. Nice to hear that you were able to help get a criminal convicted!