I'm a Brit living in California and I've definitely noticed this - in myself and others. At first it's almost shocking, but after a while it seems so much healthier.
The odd part is that I've noticed myself feeling suddenly shy and self-conscious upon meeting other British people here.
Having lived in London for a year, it was a far cry from Greece. Over here, we almost never talk to strangers, although I think I've developed a self-confidence that does allow me to do that and not sound creepy, nowadays. I've found that, in the UK, you can talk to anyone at the pub and it's natural, and in California even more so, but it's not that big of a difference.
Of course, maybe it's just me talking to everyone regardless of the norms, but people respond very well.
The odd part is that I've noticed myself feeling suddenly shy and self-conscious upon meeting other British people here.