I wanted to offer some additional information with regard to your post, in particular involving your concern over what to say if you're discovered & confronted by a family member. Diaper wearing aside, there is a sense in which this is a matter of personal boundaries. So I wanted to provide you with links to some articles, from PC's archives, on that subject as well:

What Are Personal Boundaries? How Do I Get Some?

The Importance of Personal Boundaries

4 Steps to Setting Healthy Personal Boundaries

Tips on Setting Boundaries in Enmeshed Relationships

5 Ways to Maintain Boundaries with Difficult People

https://psychcentral.com/blog/when-p...ur-boundaries/

https://blogs.psychcentral.com/imper...ur-boundaries/

Family therapist, Kati Morton, has 2 videos on her YouTube channel where she discusses personal boundaries. Here are links to these videos: