It really depends on the country. Generally speaking yellow means stop if you are able to stop safely. There is also rule that even if you have green light you

It really depends on the country. Generally speaking yellow means stop if you are able to stop safely. There is also rule that even if you have green light you cannot enter intersection while it is congested and there are cars inside. So if you enter on yellow and the other traffic hit you it is their fault. If you cannot stop safely then you hit the pedal so that you clear the intersection asap since stopping to full stop in the middle of it is bad idea.