It's a little hard to make out, but if you look at the photo of the ARA, those aren't 100-pin connectors -- they're more like USB connectors. Power + Data = 4 pins. So not all that hard to line up, especially if you have guides in the screen portion to slide in your modules. And unlike USB, there'd only be one way to orient the pluggable module. :)

My chief concern would be pocket lint getting in there.