It never has enough proof, so no.
After searching for quite a while, I haven't found the answer to this question. Let's say person A buys an account for $5, the account is still active and person B (original account owner) finds out someone is using their account. Person B then reports to Riot that someone has used their account and played ranked + deleted all my friends, etc. Will Riot then find and perma ban the person who used Person B's account?
It never has enough proof, so no.
From my experience, no. However, I'm sure if you're a repeat offender you may be banned.
there's a low chance
They can find out what accounts are accessed to your IP address. So it will link back to all your other accounts if they find out
I'm pretty sure when they see a certain amount of IP'S on a single account then they will assume something's up but other then that your good I'm pretty sure!