John, lots of discussion on this subject on LML and other sites.  Basically, the static charge builds on the flight surfaces, in this case your rudder.  Unless you have an anti-static primer (for fibreglass components) then the charge will build until it sparks off the airframe or finds some other path to migrate to.   The anti-static primer takes the charge and leads it to the static wicks.  It only has to travel the thickness of the paint to the primer and then the primer conducts it to a point where the static wicks can take over.  Most people in fair climates don't seem to have a problem.   In the flight levels, dry precip, snow, rain, virga, low RH you may have issues especially if the static is popping near an antenna.   Paint systems for aircraft are well engineered for static and all the major aerospace paint manufacturers have systems to deal with composite aircraft and static dissipation.  Some of the builders here have used those systems and described the components on LML.