I recently installed the Booster Plug, already have a Remus exhaust which I ride mostly without the baffles. No x-pipe, no airbox delete (German regulations suck).
However since i have the Booster Plug a friend who rode behind me made a remark about smelling fuel. I personally didn´t notice anything, least of all more fumes. Might be coincidence. But as you pointed out correctly the bike does run richer with the Booster Plug. I´ll keep an eye (and maybe an nose) on the subject.
Doesn´t matter what you ride... just ride!