That's exactly the problem. Apple doesn't want any notification of this to be visible to the user in the app. The fact that the app handles the user's email isn't guaranteed to be a relevant distinction to the random reviewer who is tasked with reviewing the app.
Apple has not spelled out clearly that this is okay for them to do, which means that it is a risk.
The user would be receiving a literal iOS notification from this app that talks about upgrades available outside the app.
Apple has not spelled out clearly that this is okay for them to do, which means that it is a risk.
The user would be receiving a literal iOS notification from this app that talks about upgrades available outside the app.