I'm pretty sure that's what your parent is describing.

In my case, I often spend multiple days at my parents' house. Now, I mostly don't order online, but sometimes something comes up and in that kind of situation, most merchants will have me go through the verification.

Since this doesn't happen frequently, I'm more likely than not to not have hauled my secondary phone, especially since I very much prefer traveling light. Now, could most of those occasional purchases not have waited for my return home? Eh... most probably could've. Doesn't make it less annoying, though, for no good reason.