I'm brand new to Collector, so maybe I'm missing something.
I know Collector can be used when you're not connected to the Internet. I created a map in ArcGIS Online, made sure my iPad was connected to the Internet, then downloaded the map to the iPad for offline use. Then, to learn the process for collecting data while offline, I signed out of ArcGIS Online and turned off the iPad's Internet connection (to simulate being out in a remote area that has no Internet connection). Next, I went outside and started Collector. It presented the opening screen, prompting me to sign in to either ArcGIS Online or Portal for ArcGIS. But in order to sign in, the iPad has to be connected to the Internet. So if you're out in the middle of nowhere without an Internet connection, how in the world do you get past the sign in screen so that Collector starts up and you can use it?