OP here. Yeah, "copyright law" was a lazy shorthand, but it reads better than "tortious interference."

PureGym's T&Cs [1] have a ridiculously long "PIN abuse policy" (probably meant to stop people sharing with mates). They can cancel memberships or even retroactively charge for gym use if you "knowingly provided your PIN to another individual."

I'm not a lawyer and don't fancy being the test case for whether entering your PIN on a third-party website/app counts as "knowingly providing" it. Given how their app works, I suspect they might just ban a bunch of accounts instead.

Though now that I think about it, the squat racks are always packed, so maybe I should just distribute the app to people who go at the same time as me.

[1] https://www.puregym.com/membership-terms-conditions/

> I'm not a lawyer and don't fancy being the test case for whether entering your PIN on a third-party website/app counts as "knowingly providing" it.

I guess I'm assuming that you would design the iOS app to collect and store the PIN number on the device, and never ever share it, since (if I read the post correctly) that's all you'd need to get to basic auth. I take your point that that might still be considered "sharing with a third party" but honestly I suspect that (a) they wouldn't notice for a long long time and (b) they would typically start by sending a c&d, not hiring a team top-notch lawyers and going straight to court unless you're really wealthy and there's some prize to be had for all of those legal fees.