I don't know if this is regulation for all McDonald's or maybe just those in Japan, but it's probably one of those "Food will be made/ready in this amount of time or it's free" situations. I know my local Safeway Deli says if it takes more than three minutes to make a sandwich, it's free.
I know how this is. I use to tell my friends all the time "Hey, you're suppose to get this for free if so and so happens" and get all paru paru since I never get that lucky. Then I did, and when I went to claim my free food...I suddenly got all nervous, and a crowd came in so now there's people behind me waiting. Then I apologized for no reason and just went back to my table, afterwards I was thinking "what the hell just happened?".
Japanese people are especially all about not making a scene. Lightning is soo embarrassed to even be asking for something for free when it's the store's in question policy.
Me on the other hand? There are a couple of stores in my area that have some kind of "If you don't get a receipt, your food is free" kinda deal and you betcha your ass I raise a stunk about whenever I didn't get a receipt. Line behind me be damn'd.
Got food for free about 5 times now. Pretty sure the stores hate me now.