Even if all the phonelines are underground all the way to the exchange? 
What; and you think the several million volts [from a lightning strike] cleanly dissipates in the couple of feet between ground level and any cables in the ground, without sending any pulse up the cables?
But if you're so sure; go ahead - try it
Plus; in open space, wouldn't a large amount of metal below ground be more likely to attract the strike away from an area which is just dirt?
Ade
ADSL2+ with BE
DL Sync around 4.8Mbps
UL Sync 1088kbps
DG834GT with DGTeam firmware