Its not a bad strategy, require new games to support the latest firmware and have each firmware do something to stop pirates. Sure a new custom firmware will be out in a day or two, but then a ton of people need to download and update their PS3's with the new custom firmware. Personally id also look at some way to identify the previous firmware version and do a validly check before installing, and if the validly check fails, or isn't done in a reasonable time frame (eg. /- 15% the time it takes on test machines) then brick the console/kill it if possible.