Disconnect landline, old style lightening arrestor w/ground

[tony]

Hi,
A question about disconnecting the landline. I've read as many of the posts I can find re: disconnecting the landline. We have the old style lightening arrestor type junction between the phone company wire and our house wiring. The wires connect individually around threaded posts under hex nuts. There's a picture showing something similar to our setup at this great site http://www.mi-telecom.org/distribute.html about 1/3 o the way down under "lightening protectors". In our case, the green and black wires are connected to the centre post.

Question is, should I disconnect the green and black house wiring that is connected to the ground post and fully separate the house phone wiring from that of the phone company? Or is there any compelling reason to leave the house phone wiring grounded?

thanks.