You are reminding me of another reason I dislike rotators.
The reality is that vendors of rotators will instruct you to use some form of discharge or grounding protection but few seem to produce or sell such a thing. Here are two choices:
http://www.dxengineering.com/Parts.a...tNo=PPC-IS-RCT and the design by Eagle Aspen that sends control signals and power via the coax.
http://www.solidsignal.com/pview.asp...0Rotators&sku= (I have heard mixed reviews for the E. A. rotator)
Telco provides this type of protection every day using several different versions of this:
http://www.bourns.com/data/global/pd...56M%29revA.pdf The challenge is to find a retail source. Graybar is a possible source. (A traditional phone line will operate at a maximum of 52 VDC when idle, 'ringing' applies 90 VAC between the two conductors. Not that much different than rotator power and control.)