This is absolutely incorrect.
Motorsports racing rules say it is BOTH car’s responsibility to avoid collision. The car in front should achieve this by claiming and maintaining a racing line. The car behind should achieve this by respecting the racing line chosen by the car in front.
You see, racing line is the key in motorsport racing law. Just like in real world routine road driving, keeping in your lane is the key and if you do an lane change causing another car to hit you, it is your fault no matter you are in front of or behind the other car.
In motorsport, racing lines serve the same purpose as road lanes. Why people not simply draw lanes on the track? That’s because racing lines are dynamic and context dependent, for example, in certain corner, outside entry → late apex → inside exit can be a racing line, while inside entry → early apex → outside exit can be another racing line.
As I said, both cars are responsible for racing safely and the front car’s responsibility is to claim a racing line and keep it:
For example, on a straight, racing rules only allow the front car to do one line change. If the car behind is approaching you on a straight, you are allowed to change your line once to either create difficulty for his passing or occupy a better entry of the following corner, however, you change to this racing line means you claim this line and tell your opponent free to drive other lines. If you do a second line change and your opponent rear end you, it is your fault because you drive into your opponent’s line.
Another example: you are leading and your opponent is partially overlapping with you in a corner. You need to keep your racing line and he needs to respect yours and not driving into yours. However, if you, for example, switch from outside exit to inside exit and causing your opponent who is already at the inside exit line to hit you, then it is your fault even you are in front.
I 100% understand that many online Forza players do believe it is always the behind car’s fault. However, that is totally wrong and I really think Forza’s should provide racing rule lessons before allowing people to enter multiplayer lobbies…