They won't read it...
We've had fibre put in at work the other year, everything they put in the ground was covered with writing and symbols advertising it as being fibre every metre or so (although doesn't help that the external tubing they lay to blow the fibre down looks like a bit of beefy SWA mains cable).
Wouldn't be surprised if even if they could read they nicked it "just incase" BT were lying in some sort of attempt to put them off...