To me, it isn't the frugal things we do that make it stealth wealth - I did most of those things when I was scraping by, when I was starting to thrive and just carry on through.
It is people's assumptions and reactions. Especially those moment that you want to say something, but it would either be judgmental or completely out yourself.
People who think we don't have any skin in the game when it comes to taxes. Because who would have a high net worth/income and choose to drive an older car or have a roommate, much less both?!
Relatives who say "it must be nice not to have car payments," but they update their car every other year.
People who can't get their head around the dichotomy between the luxury of a boat big enough to live on and the sadness of "having" to live on a boat. We must have finally dug ourselves out of a hole when we started renting a condo, too, how exciting. Uh, no, and it seems rather insensitive to suggest that landlubbing would be a move up in the world when everyone knows I love my boat.
When someone with a more luxurious lifestyle than you says "we can't afford X" and you respond with "we choose not to spend on that." Very borderline, but most people do seem to take it as a lesson in gratitude, rather than a brag.
When someone with an upper middle class lifestyle makes comments about how the other half lives and they mean richer people, not literally the other side of the median. Oh, I'm sorry, when you started with that, I thought this was going to be a conversation about inequality or gratitude, not a screed against the .1%.