Wouldn't that be staggeringly expensive?
I think the main problem FIFA or whoever face with implementing this technology is how far down does it go? Surely they can't just give it to the top leagues, so where do you draw the line? If the prem has it, the championship should have, so should leagues one and two, do the conference get it? Below there?
Ideally it would be every game in every league, but the use of hawkeye in tennis and cricket isn't universal and it certainly improves the decision making when it is in use. Why not just prem/champs league/major championships? Cost-wise surely it couldn't cost that much more than those stupid headsets, or the little golf carts they bring on to carry players off the field.