How would I know that this app isn't siphoning off my ideas to its own server? Not that I'm saying it does. Just curious how people might do traffic sniffing a

How would I know that this app isn't siphoning off my ideas to its own server? Not that I'm saying it does. Just curious how people might do traffic sniffing ala lil' snitch on an iOS device. I guess one way is to set up your own WiFi network on a desktop machine, then connect to that network, and also set up a proxy like Charles on the desktop to watch traffic? Not sure this configuration works though. Anyone done something like this?