Are you guys running the trailer lights straight off the foci tail light power? Or are you using the foci tails to activate a RELAY?
Personally, I don't like the idea of the car's internal lighting power being extended to an outside body (imagine if a short would occur). IMO better off wiring in a relay for EACH light with it's own independent power line and SEPERATE in-line fuse just for safe measure.
Out of curiousity, what are you guys hauling in those cute iddy biddy trailers? Somehow I imagine them stuffed with picnic items or filled with ice and cold drinks.