While I do think that is a great example, it would appear that your peer group might have a self-selection bias for increased security, vs the normal population.
A quick google search leads to multiple articles suggesting that the vast majority of people do not lock their phones.
As to whether they would give you their phones or not is a different question, but I would wager that many (most?) of those who don't lock their phones would also not necessarily care if someone looks at their device, or at the very least do not take measures to prevent others from doing so.
This is a valid point, and the people I talked to tended to be younger. I assume older people don't lock their devices? Or maybe its a regional thing? In Germany I (anecdotal) have met maybe a handful of people under 40 who didn't lock their phone and one under 30 of a 100+ people.
A quick google search leads to multiple articles suggesting that the vast majority of people do not lock their phones.
As to whether they would give you their phones or not is a different question, but I would wager that many (most?) of those who don't lock their phones would also not necessarily care if someone looks at their device, or at the very least do not take measures to prevent others from doing so.