Hack and Slash
We used to have a problem with BT (this is before they span off their engineers into Openreach) where they could come on site to do some kind of engineering work; speak to reception and flash some badges and then charge in to do whatever they thought was best.
In one case they were working in a ceiling void and decided that all the other cables were in the way of their working area. So out come the clippers.
clip .. clip .. clip. (cue lots of alarms going off on security desk as they chop and short out the door and window alarms to 1/3 of the site).
then they found the nice big thick mesh armored cable. out come the bolt croppers (I never found out why they had those in their standard toolkit); clip.
Cue 1/3 of the building dropping off the site LAN as they shear through the F/O links between the racks; and the spanning tree has conniptions trying to reconnect.
We eventually had to force BT into coming back on site with a F/O splicer (incredibly expensive back then) and have them splice the line back together.
Their argument was "anything in the ceiling void that is in our way can be removed per our access agreements". Our response was to ban them from unaccompanied work on site.