It does appear to be a UK thing. This is from the UK Highway Code. I'm not finding a US equivalent.

  114 You MUST NOT use any lights in a way which would dazzle or cause discomfort to other road users, including pedestrians, cyclists and horse riders use front or rear fog lights unless visibility is seriously reduced. You MUST switch them off when visibility improves to avoid dazzling other road users (see Rule 226).

  In stationary queues of traffic, drivers should apply the parking brake and, once the following traffic has stopped, take their foot off the footbrake to deactivate the vehicle brake lights. This will minimise glare to road users behind until the traffic moves again.

In stationary queues of traffic, drivers should apply the parking brake and, once the following traffic has stopped, take their foot off the footbrake to deactivate the vehicle brake lights.

I’m sure that might have been fine 30 years ago when cars had actual handbrakes. I doubt most folks these days can even find the little switch that activates it. Now it comes off as a bunch of monkey business.

Well found, though I'll also point out that the highway code uses "MUST" and "should" in the same way as the RFCs do.