Giovanni
Bad decision. It should be out of fuel=no reward.
The highest number of players I have ever seen is 8 and the largest part of quick races has 2 or 3 players. This means that farming resources will continue. 50% of times they will be rewarded but it will continue.
Furthermore you should lock quick races for 24 hours for those who run out of fuel twice during the last 24 hours. (Once can happen to anyone)
That's the other problem, you think you're racing a guy and it's all down to the last thrilling lap of this 10 minute race only to realise the other guy isn't even using his boost, he's put his phone down and just collecting rewards. Really winds me up! Now at least in races with more than three cars you should have genuine racers racing! ?