This tom Foolery has gone on far enough.
Half the battle is already lost, when you enter champ select and find yourselves dealing with someone in a shitty mood. They think because its champ select, they cant be reported, therefore proceeding to ban your favourite champs, or grief the hell out of you if they dont get what their entitled asses want.
The reason this is extremely important, is because this most likely determines how poor your communication and teamwork will be in-game right off the bat. That angry manbaby from champ select, may not want to gank for your lane at all IF he's jungler, or may grief you further ingame or even tax you by stealing your CS.
When you report them, at least someone from Riot can see how negatively they impacted your team from the start.
Its extremely sad because its things like this, that Riot needs to see how their system is easily abused.