[basch]

Im still not convinced that Instagram hasnt figured out a way to identify you and your friends, and has decided theyve used up their trial images.

But maybe you are right, maybe you are part of some kind of A/B test to see if an immediate loginwall, with no trial or sample, increases or decreases sign ups.

[rpgbr]

It's a possibility, and I shouldn't doubt Facebook's reach. Anyway, these friends and relatives I've asked for help they all have Instagram accounts and use the app regularly, always logged-in, and yet that popup showed up in their first attempt to see a picture logged off.

[basch]

I would expect all those people to have a cookie or equivalent tracker saying "this person has been to instagram before"