Why not HWID ban repeat offenders?

We all know how easy it is to bypass an IP ban and the reasons why Riot doesn't issue them (game lounges, college dorms)... But why not issue HWID bans to people with 10+ account bans?

I'm curious about this because I've seen LOADS of games ban players by their HWID and in most cases it's difficult or downright impossible to reverse if done correctly. That means they'll never be able to create another account for that game on that hard drive. Ever again.

To bypass this, they would have to either purchase a spoofer (which can get very expensive) or buy a new hard drive (also expensive).

I'm asking this mainly because I have a friend who has over 1000 cracked accounts on League and is an avid scripter. He still plays the game every day, and whenever he gets banned, he just swaps to a different account. He's ruining 8+ games a day for 9 other people doing this. (He's still my friend because at the end of the day, League is just a game.)

I'd like to know everyone's thoughts on this. Thanks in advance.

EDIT: The collateral damage is worth it in these cases IMO.