What they do to determine if you get perma-banned and what to do:
1 - If you're reported, your account is flagged for revision. So either 1) the system will take care of you if A LOT of people report you in such a time span. 2)the actual staff take care of you, checking your chat logs, previous behavior, etc.
2 - As Gakupo said, if he got banned on the FIRST issue of friends "reporting" him, then he was NO WHERE close to NOT being banned. There must have been A LOT more reports done.
3 - Problem: NO STAFF will transfer ANYTHING, unless you are EXCLUSIVELY allowed to for whatever reason. Specially ban issues. Just because someone dished out 300$ for example on skins, doesn't mean Riot has ANY obligation to transfer if you get banned or suspended "joke" or not. It'd be unfair. Others that went to ask and were denied would have to be satisfied. ALL of them. Not happening.
4 - Joking is good, if you VERY explicitly say it. In case of your friends, they can be suspended/banned themselves for abusing of the system.
5 - Someone can't just be unbanned, Riot staff has to review the case, if they do, and check the chances of it happening. Again, having to check previous behavior, reporting stats, etc.
Just my 2 cents.