No, never under any circumstances.
You can look, but DO NOT TOUCH!
People I know, sure. Strangers, absolutely not.
I let anyone and everyone hold it. It's just a $299 phone.
If they drop and shatter your iPhone, Amex to the rescue!
Good gracious. I hope an emergency never comes up for you and you forget your phone and need to borrow somebody else's phone. Hopefully for your sake they'll never react about their precious phone the way you react about yours.
How do you react when others ask, "May I see your brand-new iPhone?"
Two days after getting my phone, my dad asked to take a look at it. I handed it over and the first thing he did was try to bend it.
I never forget my phone, I have never, not one single time. Ever.
Also I can't think of any emergency that I particularly would be in where there wasn't some type of major business, family member, or friend nearby.
I wouldn't ask someone to hold/use their very expensive phone, especially someone I don't know.
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I have never damaged a phone, it would be just my luck that I let someone use/hold my phone and they drop it and shatter it, guess who's stuck with that problem... not them.