If you have a Suitelet used by multiple users where potentially more than one user could select the same lines to be processed (offloaded to a background process (Scheduled or Map Reduce Script)), what approach would you use to prevent that multiple users process the same lines creating duplicates?

Ive solved for a similar issue in the past by fashioning a concept of a “cache” custom record that I referenced at strategic points of the user experience to prevent submitting duplicates. The issue with tagging up the lines with a custom field here is you are relying on timing to be perfect. Record just housed the internalid and other relevant meta data