Excellent, security education is working. The correct response to someone trying to convince you to accept a self-signed certificate is extreme skepticism; don't undermine people's understanding of good security practices.

> It seems that elderly nowadays are super vary of any hacking or scams. YMMV.

I'm sure you meant "wary". How amazing, education really does work. There is such a thing as overabundance of caution. But it's possible further education could encourage users to apply more balanced caution policies.