Spatchcocked chicken is on my short list of things to try. I don't remember where I saw or read it, but someone said that they ran criss-crossed metal skewers through the spatchcocked chicken to keep it from buckling up on the grill. Looks like yours stayed pretty flat.....nice chickie!
Interesting. I've actually never had one buckle up on me, and I've done quite a few. Bacon, yes - but never a spatchcocked bird.
There's actually very little holding it together after you crack the wishbone. I can't really imagine how it would buckle.....unless maybe they didn't snap the wishbone first?