If it is an existing building and the telco or CATV are already properly grounded and bonded, then 250.94 exception doesn't require the intersystem bonding termination to be installed, however you can install one at the service for other additional buildings if needed.
It's a rare event that it's done correctly with the current requirements for size, length and connection location, etc, especially in older buildings, but sometimes you do see it.
I guess they figure that if these systems are already properly bonded, then leave well enough alone.
I've noticed that around here, all of the telco ground wires have yellow tags on them at the point of connection that say "Warning, if this clamp or wire is loose or removed contact the telephone company repair service."
This seems to indicate that they want ultimate responsibility of the grounding and bonding for their systems.
