alt Hacker NewsAdd to that list respecting the TOS of the user's ISP so that the user does not get banned, and providing some sort of remuneration if illicit activity through the proxy causes problems for the primary user, and then _maybe_ you could call this all not shady as fuck.
If only ISPs would actually crack down on (usually unwitting) users whose systems are participating in a malicious botnet or otherwise have their networks compromised. They could offer temporary disconnection + anti-malware support to get the user cleaned up, if they actually gave a shit.