That is a good point, but we are back to the question of how often do you open the rear door? With the door closed, the weight is distributed through the hinges, the frame of the door as well as the latch, and it is static. I have seen Tom's photos, he used his to haul stuff so he might have used the rear access more often. I have put only 25K miles on my truck over the last 4 years. She doesn't get driven much, and at least 10K of that is just the drive across country and long drives to URE and back.
Better safe than sorry I suppose, but I wouldn't let that stop you from getting the mod done. You can always add the support later.