Well, actually — yeah. At this level, and especially in the context of the good humor that this was apparently greeted with by all concerned, referee included — yeah. Mind you, I say this because I don't buy the proposition that the fouled kid really embellished. If I did, I would have been talking to him about it in the first place, so the "reenactment" would never have occurred.
YMMV but it looked more like an attempt at humor than an act of dissension towards the referee. It looks like a simple u10 boys game and in my experience, they are joking around more than acting bad. Granted, if this happened again or by other players, I would have a conversation with these boys. No plastic needed unless I could not manage it verbally.
I don't see good humor. I see derision directed at the referee. While I'll grant that I haven't worked many U10 games, I've never seen anything of this sort in U10 games. And no, I wouldn't caution for it. I would, however, have a conversation with the player explaining why his behavior is unacceptable.
Interesting. That starts to feel a bit different — I thought it was more like U10 or 11. Still though, even at that level, I think it's a temperature-of-the-match and temperature-of-the-situation thing. If that kid made me laugh with his first flop and, smiling, plays to my amusement and does it again, I'm (probably) not going to turn that cheerful atmosphere ugly with a card. That's the way I read the video. But if the tone is more argumentative and confrontational (and disrespectful), the card is probably coming out the first time, so there is no second time. Bottom line, YHTBT on this one. If a U16 player pulls this on me, I'm probably going to be smiling broadly as I show him the card. "That was very well done. Here's your certificate of recognition."