It's all about the mindset of the engineer!
All of these issues would be of no consequence if the engineer closing the cowls did so correctly! The latches have not been proven to be faulty, ie. open, having been closed correctly.
Cowls should be either open on stays, or fully closed and latched!
The a/c operator demands an on time departure, its quicker to open them, have a quick look, drop them back down, besides, you're on your own and its tricky/dangerous to try and put the stays in on your own. You need to open them again in a minute anyway so you just leave them like that for now.
It's all about the mindset of the engineer!
It is madness to drop the cowls off the stays and say to yourself ill latch those later!
You've just dropped the cowls down and are about to latch them....
Enter dispatcher,
"Eng? The captain wants you and we are holding boarding until he speaks to you, by the way we have a slot and the crew go out of hours in 30 mins. "
Enter refueller..
"Eng? The total fuel has stopped short by about 500 kilos and I've got a dash 8 on a quick turn round screaming for fuel!"
Enter loading supervisor...
"Eng? The aft cargo door won't close"
Ring ring..
"Allo, MCC here, the xyz123 will be with you in five minutes with a bev maker leaking all over the fwd galley, it will need a zonal inspection in the avionics bay"
That is not an exaggeration.
It's all about the mindset of the engineer!
It requires a discipline and mindset that I'm afraid is not, nowadays, brow beaten into you during the modern abbreviated apprenticeships.
Perhaps, but it can also be brow beaten out of you by non technical aviation "professionals" who have no concept of the consequences when interrupting any maintenance task (or even a flight deck briefing).
When driven by performance related pay and an on time departure is a must, some just really do not care.
I make no excuses, just trying to offer a more realistic point of view.
There for the grace of... etc.