What happens when the customer contacts you for support and is using the shielded email service. You don't know the "real" email for the account, and the customer can't email you from the "shield" email. So you have limited means of verifying they are who they say they are. So how do you for disclose account information to them if you can't be sure they are the account owner?

I assume what Apple would like you to do is to build an "open a support ticket" flow into the app itself, which either asks for the customer's "contact email", or allows correspondence directly through the app. Such in-app support flows are already pretty standard for e.g. mobile carriers' apps, I've noticed.

You send them an email to the address associated with to account with a verification code.

When I used the feature with Byte it gives you the option whether you wish to mask your email address or send your real email address.

Is this on Apple's side of the authentication? Because if you implement the web version (on a non-Apple device) and login with credentials, you don't seem to get a choice, it always uses a masked email address.

Yeah, gives you a choice when you login with iOS.

Then again most application owners won’t be that happy they have one less data point to sell.

I think if you look at most application owners (not the top 1%/10%), they don't care that much about selling the data to someone. Better to use it themselves to gain better understanding. And as long as you can reach the user, it's good enough.

But maybe I'm naive, or biased because of my location and personal wants.