I have iPhone 6S. My mobile phone and data plans are with Ting, a US-based mobile virtual network operator that uses the framework of the US-based Sprint Corporation telecommunications company. I'm currently not in the US. I've turned on Airplane Mode, and then switched on Wi-Fi. The caption "Sprint Wi-Fi" appears on the top left of the screen, and I am able to access the Internet over Wi-Fi.
How does my phone know to show the word "Sprint" in the caption? Does it read it off the SIM card, or does it get this information over Wi-Fi, or some combination of both?
If I discontinue my Ting/Sprint membership, and stop paying my monthly subscription fee, but keep the SIM card inside my phone, without ever turning off Airplane Mode, will the caption still read "Sprint Wi-Fi"? Will my phone continue to behave as before?
Are the answers to the questions above specific to Ting/Sprint, or will they remain true regardless of the mobile company I'm a member of (with the difference that, instead of "Sprint Wi-Fi", the caption "XXX Wi-Fi" will appear, where XXX is the actual mobile company)?