Who the hell is running 300' drops, we have to turn anything over 250' in for a plant extension. As far as bonding the messenger it should be bonded at the house and the strand other wise you don't have a true neutral or ground. The reason is to keep every thing the same potential, power,cable,phone,house. Ever see a hum-bar go away when you take the ground off the ground block? Thats a bad neutral in the house some ware and it's using the cables ground.
If everyone is thinking alike, someone isn't thinking.
This is CABL.com posting #194658. Tiny Link: cabl.co/mYNO