Some controllers already do some similar things, more like shared secrets though. It's common in the brakes. There is some sequence of commands that have to be

Some controllers already do some similar things, more like shared secrets though. It's common in the brakes. There is some sequence of commands that have to be sent first otherwise later commands will be ignored. The problem is that 1) you can wire in a scope and watch 2) just try every possibility or 3) use the diagnostic/test messages instead that accomplish the same without all of that.