It has little to do with exhibitionism. It has more to do with the fact that despite hanging out with AB/DLs, I'm the only one with continence needs anywhere near as bad as mine. When we go on long journeys, it often may not be possible to accommodate my needs. I live in Australia - there are stretches of road without publicly accessible toilets along which it takes more time to drive than I can last between diaper changes. As a result, it's not unusual for us to stop for a few minutes so I can be changed on the back seat.
Partly as a result of this, it's also more common for me, individually, to be changed around others even when we're not travelling - because it's so normalised for that to happen, there is little point going to the inconvenience of hunting down a private spot if it's just our group. If it were anyone else, it would be weird, but not with me.
As an older kid still in diapers. I was changed many times in the ladies room. There were times when my mom changed me in the back seat of the car when I was six. There were a few times I was changed on a park bench, or even on the ground on a blanket.