Yes, I know I can add specific exceptions, but it won't work for me. I'm developing a magazine app where advertisers want their URLs open in an internal browser, so I can't possibly know what those webpages will be in advance.Anyway, I don't take anything for granted. As Shai say, you can be rejected for the most weird reasons, depending on which tester is reviewing, that's why I want to avoid any kind of problem in the first release. In my experience, updates are more easily approved.
NSAllowsLocalNetworking
(see https://developer.apple.com/library/content/documentation/General/Reference/InfoPlistKeyReference/Articles/CocoaKeys.html).