Left a comment there, but may as well copy-paste here: A few years ago I was working on a competition with a grand prize of several new SUVs (part of a product

Left a comment there, but may as well copy-paste here: A few years ago I was working on a competition with a grand prize of several new SUVs (part of a product launch for the vehicle). We did a very basic version of the “riddler.com” model (remember them about 12-15 years ago?) where our partner websites would put ‘badges’ for gamers to click on. Each badge was worth some number of points. Some smart souls figured out that the badge numbers were somewhat sequenced (we had allocated up to 10 badges per partner, so we would start at ‘10′ for instance and work our way up). Scripts were written that would hit our server each day and collect the maximum number of points available. The scripts weren’t that smart though, and there were gaps in the rewarding badges. Our ‘fix’ for this was to create new badges in the gaps that were worth massively negative numbers of points. In one day, the most problematic players vanished.