Nobdy would care if its legal or not, Link, we all burn CDs and thats illegal, if a MW user would see this topic he'd explode laughing and would think youre stupid or something, why make a big legal thing about a game? so what if it ruins the game??? avoid them and ban them if you want.

If you change the pos addresses, it wont help because people are making more and more programs as you said.
I recomend (this is how it is in a hacker-infested RPG i know) that each time the game is run it will use diffrent addresses for everything- no more trainers.