I didn't say any kid, but rather one's own kid - whether they can or cannot be trusted is mostly a parenting issue, so different people have different experiences.

But yes, me and my siblings would often do grocery runs for our mom, with her card in hands, and I also think nothing of handing my own card to my wife (who already knows the PIN), or mine or her siblings, or even some acquaintances, because I trust them.

The larger point (even larger than my previous comment) is that, contrary to what cybersecurity (and especially cryptocurrency aficionados) community believes, the real world runs on trust. Trust is not a bug, it's a feature - an optimization that makes societies and civilizations scale. Trust has its own limits and structural complexities, it has its ebbs and flows, but it's absolutely vital and systems that do not support it (or try to eliminate it) simply gets worked around. Not out of spite, but out of necessity - otherwise nothing would ever get done.