My Walter Mitty version is that I lock eyes with father and mother and say, "REALLY?????? WHO'S IN CHARGE HERE?" and see have them both realize after this shock that the only thing to do is to grab his little ass and leave without getting a goddamned thing!

But, that's me….

These parents seem very much in control of their emotions. They are responding in a very understated fashion -- don't presume it is ineffective.
Some parents have found that if they engage with the child and say no and other things, the kid behaves worse.

I don't think you should presume that the parents caved in and got him the video. The mother was reviewing the cover pretty carefully.

The mother also seems to have some kind of punishment in mind when they get home -- he will be put to bed.

at least in my opinion, their understated response is extremely ineffective because this kid obviously feels very safe and comfortable talking to them in this horribly rude, piece of shit way.
and he has no qualms about speaking to them (or at least his mother) around other people/strangers/in public.

part of the reason i assume they got the kid the game was because 1. he didn't say shit about it--there was no more demanding, insisting, or complaining, and he was standing beside me so i would have heard it, and 2. when he looked at me he was fine--not angry, not upset, not unhappy. it's pretty easy to presume he got his way in all this.

i don't know where the mouth on this kid comes from but i remember i had some neighbors whose little boy used to hit and kick his mom in fits of anger and rage. (he was 3, 4, 5, and maybe 6--they finally moved away). she always seemed to tolerate this, i don't remember her ever really punishing him for doing that to her. we found out, just before they moved, her husband used to beat the crap out of her every now and then. like father, like son. i assume the child thought he could do it because he had probably seen or heard his father treating his mom the same way with the same disrespect.

The game was inappropriate; mom said no. Then turned around and bought it as soon as the kid started making a fuss. He has just been taught that if he makes a fuss, "no" means "yes." And if he's doing it at that age, she's more likely reinforcing what he already has spent years learning.

He'll deal with the "nap" once he gets home. Putting him to bed may seem to her like punishment, if she even gets that far, but he may not care about that punishment, because he already won.

When he first made the fuss, had the mom then said, "I'm sorry, but you can't have this particular game. If you continue making a fuss about it, we won't buy you *any* of the other games either."

And then followed through. Kid gets louder, tone worse, etc. then mom simply asks husband to hang onto kid while she returns the games to the shelves, and they leave immediately.

One or two incidents like that and he'd get the message.