Blizzard would lose players of they ban IP to everyone who cheat. Its a way for them to rise that revenue ban players and players create new account and buy the game again.
Pretty much blizzard have you HWID each of your HARDWARE has its own ID. The only way for you to clear those off is to change the hardware HD, bother board, SSD, CPU, ram, GPU or change the Hwid.
If you're cough of cheating your HWID is flagged. Once you cheat again since you've been flagged already.