It's a good point, also the cap has a weird rippled skin affect when they move their head.
However let's face it, from 6 feet back or so that's basically the look that is perceived, and pretty much the idea when you walk into a room (and first impressions are hard to shake).
So yes indeed their heads look big and stupid, so the basic desired affect is pretty accurate.
I just think that most of those guys have got a fair bit of hair under that cap so it's making their heads look disproprtionately bigger and not an accurate representation of what they would look like. Should have got them to actually shave it or found 4 guys who would. Too many men haven't got the guts to do that. Also, what's with the unflattering long hair left around the sides on two of them? I think when you get to NW6 then if you're young you buzz it all very short...like max grade 2 or 3 on the sides and if you're older then it's not bad to have it a few grades higher but longer starts to look untidy.
Also..is it me or did they deliberately choose some of the geekiest guys going for this video (aside from the asian guy). Definitely no 'gymcelling' there.