I was alone, I took only hand luggage and I was walking through either JFK or Newark- I went through passport control and was walking for what felt like 30 minutes, when I realised that an exit was very visible and there was a cab waiting; the only barrier was one of those clip/pull barriers that they use to segment queues.
I asked a nearby cleaner if it was OK to exit because I didn't “feel” like I had exited the transit zone yet. The cleaner was appalled that I would even dare to ask and indicated that I needed to continue on the path designated.
The thing about barriers of that type is that they're always sort of optional in the UK, its usually a recommendation (albeit a strong one).
I continued as planned and came to customs and baggage claim.
I reflected on the fact it would have been astonishingly easy to just leave.
Another time I was in LAX and Air Force 1 was there at the same time, I was not allowed to hand in my drop luggage to the baggage handlers and instead had to take all of my goods (including a pocket knife and several containers much larger than 100ml) onto my flight- which went through security with no issues.
The US is very confusing to me when it comes to airline safety measures- despite europe following their lead I feel like europe is much more consistent with the level of enforcement.