John; Here's a helpful suggestion offered to those to avoid putting in duplicates.

When I receive a slot card RR, the first thing I do is to put all the cards received in alphabetical order by casino name. That way I can easily review and compare them to which cards are in my collection alphabetically and which ones are listed in Carolyn Donley's Book without having to go back and forth, back and forth, turning album or catalog pages.

When there are cards I want to introduce into the RR to replace cards that I have removed (which may look similar to cards remaining) I merely place a yellow post-it note with a short description of the difference(s) on the variation card. If the rules accompanying a slot card RR specifically states NO DUPLICATES, it means just that. There is absolutely NO reason that duplicate cards should be found by the SECOND person on the Round Robin routing order list. If there are, there is only ONE person who could have inserted the dupes.