How can I verify that the NFC tag/ QRcode iOS app I am using is not spying on the information I write on my tags?

This would be particularly relevant for stuff like wifi passwords. Admittedly it is very unlikely that the developer lives next door and just waits for a chance to get free wifi at my home but my question could also be understood in broader terms: Does Apple verify and/or declare that developers are not spying on users?

app apple developer developers door free home information ios nfc passwords privacy qrcode question spying tag terms verify wifi