Advertising Opportunity for Player Created Stuff!

I was thinking with some of my friends that during the load in screen instead of the Summoner Tip, or whatever shows up in the middle of the screen, Riot could show a player paid for advertisement that could be directed at the level of player you want to attract. Just off the top of my head summoners could promote their streams that way, upcoming tournaments could be advertised, and higher level players could promote their coaching. I am sure there would be other uses for this, but I think it would be a great way to not only increase revenue(Riot) but also help more players get their creations and ideas out there, if they were willing to pay for it. Now I am not sure what the cost of such an ad would be, but I feel like there could be multiple different brackets of advertising depending on how much the summoner is willing to pay.