So I won't go into too much detail but I work for an AASP (Apple Authorised Service Provider). I do not work for Apple but I've been trained by someone from Apple to the same level as an Apple Genius/Technician/Engineer or whatever they call it! :tongue:
Anyway the easiest give away is the home button! Just from touching it, it's an instant give away that it's a fake screen. I've gotten pretty good at guessing just from one touch! But the main thing is when we open the phone it's pretty simple to tell from the way the screen is made i.e. stickers, missing screws, missing ribbons, etc... We do what is called a 'VMI' on the handset, this is a Visual Mechanical Inspection on the device, both exterior and interior. It's basically a guide given to us by Apple to check for things in a handset and based on what it passes, we can then tell if a part is genuine/fake or whether an iPhone is under/out of warranty
As others were saying above, the 6S and 7 have a special seal which is for 3D Touch to work properly (not for waterproofing as stated above), which when we open the phones to check is again a sign the phone has been tampered with as it's pretty obvious if the seal has been broken! We often get people who will have a faulty iPhone but a fake screen, when we ask they will tell us it's genuine so we repair the phone free of charge under warranty but when we open the device we can pretty easily check. Apple allow for us to change a fake screen for a genuine screen for £120 (~$155) or £140 (~$180) for the Plus models (it'll probably be cheaper in the US as taxes here in the UK are higher and Brexit has ruined the value of the Pound)! Once this is replaced we can repair an issue, we don't like to repair iPhones with 3rd party parts so much because a lot of the time 3rd party parts are the reason an iPhone will not work properly for example a fake screen may drain more power or damage the logic board/connectors, etc... Hence why they will ask for a screen repair to be done first!
I've never come across a fake screen that fooled me or any of my colleagues (screens will eventually get checked by Apple directly at some point who feed back to us if we were right/wrong and in all my time we've never had any wrong). If you try to trade in a phone with a non-genuine screen (as a fully genuine working iPhone), I would heavily advise against this as it is extremely unethical and at some point the person who is helping you will get in trouble for your dishonesty and their company will lose a significant amount of money, so yeah just don't!
Having seen a lot of iPhone repairs over the years, I always recommend going official as unofficial screens might save you a small amount of money but 1) the quality is never as good and they're not as responsive 2) they break easier (or peel apart) because they're made from cheaper materials 3) they're probably causing a lot more harm in the background than you realise and 4) each and every millimetre of the screen wasn't designed by Sir Johnny Ive!
![Big grin :D :D](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Go official and save yourself hassle, it doesn't cost that much especially if you want to save money long term on repair costs, why spend so much money on an iPhone to ruin it with a cheap shoddy 3rd party plastic screen!
I think that about the extent of information I can provide on this topic without getting myself into any trouble!
![Stick out tongue :p :p](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
arty: