No. No it's not. And I'm very, very sick of the assumption that it is. I have been in multiple RPs, seen a lot of images, and read (and written!) stories in which this stuff is not only consensual, it's specifically asked for and granted as a favor. I have friends who *regularly* want me to diaper them, comfortably bind them, and treat them like little, helpless children unable to do things for themselves. If physical AR was possible, there are a lot of people who would want to enjoy it in an SSC environment and some who would want to stay as diapered elementary schoolers until long after the Earth's oceans boil.
There are even real children who behaviorally regress as an escape. I was one of them, a few times. I just wanted to be taken care of.
Inflicting any of this as a punishment to anyone of any age under any circumstances is evil