Re: Proxying
If It's Apple doing the MITM - they own the browser and the device. They can put whatever certificates they like in to the system, suppress warnings on their "special" certificates, and the average user wouldn't notice.
Thats the truly scary bit. But hey - it's shiny
If a public VPN provider is MITMing the connection, it's the same scenario as the user has just installed the VPN app, and probably ignored the permissions required (which will include the certs etc). Apart from tin foil hat scenarios, the only real reason to use these is to bypass regional restrictions - laudible in a few situations, but only a few ...
Biting the hand that feeds IT
