so, I may be wrong (wouldn't be the first time) but my understanding is that if you hook up to a switched wire like your brake lights than it will only run juice when the bikes on. With a switched relay you have a wire that connects to the brake light wire but does not pull power from it. That just flips the relay so the power will flow. The relay connects directly to your battery and then splits the power to some number of fuses on the block.
The Eastern Beaver guy is a WRR owner and can sometimes be found here. I chatted with him on Facebook when I had some installation problems. Real patient and knowledgeable. Although I would say if you use him as a resource you should probably buy his stuff. And no, we are not associated in any way other than I have his products on both my bikes.