The second mom or dad has a distraction, the kids will likely view this as a challenge to their ability to hold mom or dad's FULL attention, no matter what the circumstance. And believe me, they will accept this challenge and it will be awkward for the parent.
My son charmed most of the kids except for one boy who was playing by himself. This kid's dad was standing behind him and completely absorbed with texting. Not being one to ever give up on making new friends, my son tried to play with the shy boy. But he got dad blocked.
I wanted to mention a couple recent gems from my own 8 year-old twin girls, Anza and Josie. They have reached that age where their "cuffs" can come from innocence or cleverness. I'll begin with the innocent.