Really interesting to see the other side - I wonder if sometimes the perception of 'high context' vs 'low context' is really just 'not my familiar context' vs 'my familiar context'.

> Excuse me, ma’am. It seems to me that you’re in a hurry. I don’t know how long this line will take, however, I am reasonably certain that it will take the same amount of time for you to reach the head of it whether you stand 5, 1, or zero meters away from my bag, so I must request that you please stop touching it.

This does seem a bit aggro though, a friendlier way could've been to assume that she wasn't aware of the bumping and so wasn't doing it on purpose. In the US if there's a gap in a line and folks aren't closing it, that itself can be seen as rude and not paying attention (whether it makes sense or not is another matter). My personal guess is it comes from being stopped at green lights where cars in front stay parked and then you end up catching the red.