Beca, could we have more details of what actually happened? Did you tell passengers that they had to sit in the back before they boarded, or just nudge them back once they reached the plane?
I seem to remember a time where the FA's would stand in the front rows and say something like, "Please go on to the back of the plane; we need to make room for the people who are boarding after you." I thought that made sense, and I never argued with it because I preferred to be in back; DS was a spitter when he was little, so I needed to be close to a WC for cleanup. The only difficulty was getting the carseat down the aisle, but with no one in the front rows I didn't have to worry about hitting anyone until I got halfway back.
Were people getting indignant and accusing you of sending families to inferior seats, or was it just that they maneuvered down the aisle so slowly that they took too long? As you've seen if you read the rest of the thread, I favor changing the regs to require a proximity rule for the seating of children, which on SWA, would of course mean insisting that they preboard. If you define the reason for preboarding as making sure that there are contiguous seats available, it should not matter where the seats actually are (as opposed to those w/ carseats). The exit row is out for anyone with kids onboard, I agree.
I'm confused as to how they would simply stop preboarding; if you need them to preboard in order to comply with regulations, you just direct them to do it, not offer them the choice. No offense, but airlines direct passengers to do things all the time.