Most new iphones are bought by young adults with a lot of disposable cash, not teenagers, or even teenager's parents.
Apple know their market! The teens get refurbished ones, still a decent money spinner for Apple, if you put all your photos, music, data into the AppleCloud, it's really hard to get it out. So give the teens refurbished ones and they are likely to be customers for life.
Apple on the other hand are a hardware company, they don't keep their users data, governments have to take Apple to court to get them to release messages, they take user privacy very seriously, more than other mobile phone companies, they don't make money on selling users data and have incredible security measures in place for their hardware. That is what you pay for with an Apple phone, a company who, for the time being, still respects the privacy of what is on people's phones. Not even Apple can read your messages they are that well encrypted.
So I do know a fair bit about mobile phones, and user security.
Still couldn't pick out an individual model of iPhone in a line up, not even a close up one, never mind a brief look at a teenager's hand! And I don't think you can either.