I can’t get into my head the mentality that says it’s acceptable to do this.
In saying that would be interesting to see how well that closure was signposted at the start of the road as once down that road there was no turning back with the queue of traffic behind you.
As part of my job, I have worked inside traffic management on motorways, scary at the best of times. The 'TM' as we call it, has a safety zone at the start which is why you get the tapering cones with no-one working inside - it's meant to be a buffer zone. On one occasion, we had a driver pull into the buffer zone to make a mobile call..

. We were instructed by police to take reg numbers.
On another occasion, working in a supermarket car park in Bolton, we taped off areas where we were going to dig. Next day, tape cut, cones put aside as people parked in the workspace. I eventually got security to help and the night before, we built 'barricades' around the work areas consisting of upturned shopping trolleys.... Next day, you could see motorists giving us the old 'black look'.
I've said it before but we appear to be in an age of 'selfish arrogance' whereby people, referring to the tabloid cry of 'nanny state', think they personally know best and so break the rules since they don't give a s**t.