I have a Samsung Moto, and it has a very default ringtone, not really a tone since it says "Hello, Moto" which is embarrassing but I haven't made the effort to switch tones, at any rate while I will be confused if someone in proximity to me gets a call on their Moto, my experience they don't have to be very far from me before I realize instinctively, that sound is far enough away it can't be my phone, although it irritates me nonetheless.

And I've been seated eating with people who had the same phones and I realized no, it must be their phone (although I feel a strong urge to check), because my ears are able to determine direction of a sound.

I'm also old and keep getting told I'm going deaf, so my question is, are people really not able to tell it's not their phone or are they just not thinking it through before checking.

It's less the sound, and more the buzz when it's on vibration. I've never found a way of changing that, unfortunately. It's probably true for other brands, but I've never really had a phone that other people have also used, whereas now I'm in a (very small) bubble that seems to be happily converging on Fairphones...