Revelation wrote...
they had vision on all members
This is the important part. Since they had vision on Jinx, they should have been aware of he using R. Also... they should have taken drake out of the pit a bit to avoid exactly these kind of situations.
I mean, there are worse case scenarios like Ezreal's R, in which it does not matter if it impacts on some Champion or not (it does, but it still deals damage), it will hit drake, whereas Jinx's R or Ashe's R will not.
But well, overall League it is a "skill-based" game, but like with anything Luck still plays a big factor on all these things, if it did not, some players will not be where they are, by far.
Look Chess, that has 0 Luck factor, if you win it is not because of Luck, it is because you played better than your opponent or your opponent played worse than you. Complete skill-based.