That “Time Pressure” on blindside reversing is the thing…
We’re all told that we can “get out and look” as many times as we like…
Funny no one actually takes them up on that though!
I’ve seen a lot more “driver’s mirror on adjacent artic on bay” taken off than I’ve seen “trainees get out and look” let’s say…
I’d have hooted them, when I could see contact was imminment, - but alas the horn doesn’t work when my own keys are on the hook… I can’t even wind down my window and shout “Watch out!” with subtitles, either of course. 
Shunt it. If you ain’t sure - shunt it again.
The penalties come from hitting stuff - not from taking ages doing it!