Funny story, although I have to say I don't really trust a guy who doesn't like football - sorry, can't call it soccer! As a long time football fan I could point out the offside has more to do with who was where than who runs faster, but I have a feeling you won't be doing this anytime soon... and it really doesn't matter as long as the kids had fun! (And anyone knows the team that lost will always blame the ref, no matter what!)
Oh I completely get the offside rule. I just like to joke around about it.
And you are right. 50% of the fans are going to be mad either way... so no pressure I guess.