My previous bike (BMW) had a cig lighter outlet. It was wired direct to the battery with just a fuse in the line. Commonly used to power things like a GPS or heated clothing for winter riding. I used to trickle charge the bike battery all the time through it. Makes things a lot simpler when the battery is buried under the tupperware like on the beemer, or even a wing. That was a neat solution to the charging issue and it worked just fine.
Sometimes folks just don't understand the situation and instead of looking at it for the reality of the situation, just try to ridicule what they don't understand. It ain't a hardware problem, more of a software issue between the ears.