Oddly this goes hand in hand with the misguided belief that I will agree to run their cables for them, free of charge, or accept their terrible work as a finished job.
A few data cabling jobs I've done have involved the sparkies either installing the containment, or in some cases pulling the cables as well - as part of the contract so they (should) have included it in their costings. Unfortunately, these can be some of the most frustrating as a remarkable number of sparkies seem to have no clue.
One job, the sparky was moaning about how easy it must be when someone else has done all the work for them. This same sparky had installed 2 compartment trunking and taken the bigger compartment for his 2off RFCs so I had to squeeze 24off Cat5e cables into the tiny side section - and didn't have room for the phone cable that was also supposed to go through it. The trunking was (IIRC) Rehau and shaped like 3 section dado with bevelled top and bottom - except the bottom side was integral to the main trunking so without any covers fitted it would look a bit like a J in section. This made the central and lower compartments into one big one unless a separator was fitted.
He was 110% adamant that a) it wasn't possible to segment off part of the big section (it was, manufacturer does a divider for it but I didn't have time in the job to order it and wait for it to arrive), and b) that electrically he couldn't use the smaller section as then the cables wouldn't be insulated. Yes, you read that correctly, he genuinely believed that the plastic bit between upper and central sections would only insulate one way
On another job, the cowboys left the cables all sorts of lengths. One went out of the room, down the corridor to the other end of the building and half way back again. At the other extreme, one had just 6" sticking out of the wall and somehow I was supposed to another couple of yards to get it into the free standing cabinet and terminate it
And another job they gave the data cabling to the apprentice who'd clearly been given no instruction on how to handle cables (of any type). When the cable snagged in the box, he'd just pull harder till the knot came out. The cables were all sorts of lengths. The numbering was ... a bit unreliable. And he just ----ed all the cables (over 100 of them) in a big heap of spaghetti which took me a day to unravel.
But that's the bad jobs. I've also done jobs where the sparky has been clued up and we've been able to work together to good effect. Sadly those jobs were always the minority.