... Or, you could swap out only the SIM card, have a new number, and the rest of the phone is literally exactly the same.

Most kids these days use social media apps for messenging and general time wasting in class... all they'd have to do is update their phone number with the major apps they use before they come into school the next day... all the contacts are in the apps themselves, not the OS's contact list.

...

Either way, you're still missing the point that the kid's entire question line is literally a non sequitur, a misdirect, a distraction via tangential discussion.

You are falling into the trap of bothering to engage in the actual ship of Theseus 'what actually constitutes the same phone?' argument that the teacher has.

The teacher, and you, do not realize that that is irrelevant, and were this some kind of debate bro / debate club debate, you would both have fallen for a rhetorical trap, wasting time arguing over something not germaine to the actual topic.

It doesn't matter if the kid has millionaire parents and legitimately purchased and owned a brand new phone with a live phone plan every single day, and brought it to school.

Or if the kid stole phones, borrowed someone elses phone and was caught with it.

The rule is 'no phones in class upon pain of confiscation'.

...

Whether or not it is literally or philosophically the same phone, or a legitimately owned phone, or that particular student's legitimately owned phone has absolutely no relevance.

... Its like how if you bring alcohol, drugs, or a gun to a school... whether or not they are your items doesn't matter, whether or not its a single shot derringer or a full assault rifle doesn't matter.