This really is the best way. Once there's a REASON for extra security, people understand and want to learn more.
No one cares. Nobody around you understands the security, the need for it, and the requirements. They will pretend, to see your kid. And then immediately and completely stop caring. It works for making people adopt your favourite messenger, yes. But nothing else.
I too, like OP, thought I found the grail when I got my kids. People suddenly accepted using my communication preferences. Only to find years later that they didn't. They didn't care, understand, or respected my wishes. Don't fool yourself: some people do care, but that is 10% tops.