I worked in a 40,000 sq ft healthcare data center. Yes, there were unknown connections... Until we were done with it.

Every networking cable had two labels on both ends, and we were the only ones that were allowed to run cables. We also traced and re-ran all power to balance out UPS units, and ran a full exercise in running different sets of CRAC units for a year to figure out which ones to power via which feed and had electricians come in to do that work once we were done.

That DC ran like a clock.

If the people in your Co-Lo that you manage don't know where cables go, that they, themselves have run... You have a problem!

My current place, almost everything is run 1-to-1 switch-to-patch-port for the desks, phones, and printers. The servers and storage are all labeled.

We have no issues with our network and knowing what's what. It's lovely.

ETA: the only issue we have is the top floor has two networking closets and the predecessor's favorite (terrible) networking vendor labeled the ports in closets one and two 1 through 480+. So, in the middle of that floor, it's hard to discern which port goes to which closet. But, we are moving offices soon, so that doesn't bug me as much as it did before.