Yep TH - I've got over 30 years in the Telecom business, the thing is - the metal wire running through the fiber cable is a strength member only. It does not carry any signal and or voltage. I work directly with the AT&T outside plant technician here in the St. Paul area, he is a good friend, and as you said; not a good idea to break open one of those live cables - HUGE penalties for that!!!!!!
Many times fiber will run along side coax and copper tip/ring cable, that might explain it.
I have worked telcom for over 42 years, started with Automatic Electric which was General Telephones installation force in 1973 installing step offices, then #1EAX, #3, and last GTD#5 COs, after 16 years went to work for Wiltel that was sold later on to LDDS and formed Worldcom. I worked 16 years for them, then 10 years for what became Windstream before I retired, total telecom 42 years 6 months...
I was field tech, the only field tech for the company with in 120 miles in any direction. have personally located fiber cables thousands of times, fiber was not in an easement with copper, it was only fiber easement, cross country between St Louis and Kansas City, carrying 20 DS3 between the cities, had 3 regens and one pop to maintained, equipment, transmission systems were NEC and Fujitsu, worked on many fiber cuts and spliced fiber hundreds if times. It is not required to carry signal or voltage to be located it was only grounded at each splice points.....
In 1990 Missouri river jumped banks and ripped our fiber up, we had to lay over 35 miles of temp fiber tying it to fences, trees and what ever else we could find till we got through river then trenching it in the ground, working 7 days a week in 105 degree heat. We almost lost I-70 then...