Here's the deal. Raised floors throughout a five storey building have hundreds of double duplex receptacles under them. There's a cob web of extra long plug strip cords running to the receptacles, through holes in the floor tiles. Now, this isn't a computer room situation, just regular office space. I know that the code prohibits cords running through tiles this way, and I suspect it is because you can't see the condition that the cord cap is in, as it is out of sight when plugged in under the floor tiles. All sorts of loose connection mischief can occur this way, and I'm wondering if anyone has any experience in the sort of problems caused by this sort of code violation.
I think that the original reason that flexible cords couldn't be concealed was that eventually, the cords insulation ages & becomes brittle and could actually fall off.
One of the troubles that may be encountered in this situation is that the cords could be damaged right where they pass through the raised floor panel. After all, if we were doing exposed Romex, we'd have to provide physical protection at this point.
Few things are harder to put up with than the annoyance of a good example.
Not a plenum, just a continuation of room air space. No duct work or air flow under the floor tiles, just dead air space.
And yes, there is a probability of damaged cords. I've seen some of the floor openings with 3" plastic 'grommets', some without. And I've encountered several heavy boxes of paper jammed up on the cords. Looking under the tiles, I could see many cord ends semi-plugged in to the receptacles. They have about 5 duplex receptacles per 20 Amp circuit, and every available receptacle is used..so we have 10 plug strip cords running off of each 20 Amp circuit. These feed computer work stations, printers, and sometimes people think they need to put in a little space heater on the same circuit!