When it was happening I thought this was a straightforward one that wont create problems here or elsewhere, but nope haha every one is still arguing, even the damn pundits. How can they all not know football? If Sigurdson was not at all interfering, why did he follow the ball and his body behaved in ways, pretending as if he would interfere? Thats all you need to know. Not care whether he actually blocks pathway or not. He knew he was offside, he moved to cover it. By moving, he automatically comes INTO play. and hence, interferes, whether you agree to the angles or not. That is it.