a cable with a right angle end, or a stand to keep the output jack area off the ground would likely help -
leaning a guitar up against something could be a repair waiting to happen (i'd try to avoid doing that)
the 03-06 100/200 series with ES Blue & the DDSM have the output jack on the lower treble bout side
of the guitar, which i believe would have some kind of reinforcement 'patch' on the inside of the guitar -
i see the potential of dings/scratches from the tip of the cable if one is trying to plug the guitar in 'by feel'
most aftermarket pickup utilize a cap that covers the threaded end & lock nut at the outer end of the output jack -
the tailblock seems like the ideal (most reinforced) area for it to be, for if the guitar were to fall with a cable
plugged into a side-mount output jack, the likelihood of the side sustaining damage or a crack is probably quite high
the martin power supply output jack assembly terminates at the very edge of the tail block close to the kerfing -
to me, that design seems to be a bit 'lacking' (the 9V battery carrier on the ES closes with a positive 'click')
whereas the battery door on the martin just covers the bare end of the battery (not a very stout piece, imho)