As an FYI--I run my passenger pegs most the time (extra crash protection, plus you never know when a hot chick wants to wrap her legs around you). There are four bolts that connect the pass pegs to the undertray. Two are easy to access, two are a bitch due to the proximity of the header. I've only run the rear-most bolts and have never had an issue with them coming loose. If the girl on back (or boy if that's your thing) exceeds the weight limit for the tensile strength of just two bolts, my guess is she probably shouldn't be on the back anyways. Just an FYI if anyone wants a short-cut to install/de-install and is worried.
Of course, do it at your own risk--there's not much weight on that .... when riding, only when mounting/dismounting. I'm just saying I haven't had any issues. Don't sue me if a heffer falls off the back and bounces into a ditch.