Lad next to us is maybe 13 or 14 and goes with his dad and two sisters. Rarely gets rebuked for some of the stuff he says. Weirdly, he keeps his mouth shut when my wife sits next him.
On those occasions my son can't make it and nobody else can, I have the opposite issue of either sitting in my single seat or spreading across two, with a buttock on each seat but if I do that it feels like I'm being rude to the person next to me. It's not particularly comfortable either.
I've mentioned this elsewhere but the bloke next to me in my old seat in Upper East – who is a fairly regular poster on here too – was coming out with increasing amounts of racist crap, so we moved. Didn't tell him we were moving. But he might know who he is and, if he does, then have a word...