Markets still have the auto-encrypt functionality (looking at you Trade Route). Well, there's a way to avoid that.
If you autoencrypt it will send a message automatically that looks like this:
-----BEGIN PGP MESSAGE----- Version: GnuPG v1
hQEMA9kpB4A18MYbAQf/YKN39d5TQDjKir/Yzu0D5uQjBLYaNRJz6mHuVqeCNAux lj4GIgIgWMVmrZUEU0BiTptnQA4IEPWX1H2IA7JIozAtqLZz/C38vfyqbO1f1d07 cJFOJVtgxqgMCFxrqfdwlNXAvw0PIwVHsFGIx67A+UCAbm8Ecb/CRVfG5NnbwwMM bgk8t6tSVl53nJnX2bj5INd1ohz6LEEYIYfw3lH6oBqrpcIADn4gwqPsjEim6Mu3 eJ1q4g2497wIBWxbEPtBLO5CHiAwNW5W0NQ3r7Yuc/Pj4KAfr5xwgw1iwpIgeqot tMvDvBN3yTzFHCcPmfTBFflFwRrZ/GJXBPpiWi3mMtI/AduQbEalYf4bX2/LgRhF ZIN3pLUAZHqpi0iWMysTMWPnhI7hN+vsB3YiFxOmPtj4g9rfujitFKbWX/N6CR3S =8gEg -----END PGP MESSAGE-----
Notice the version line, you can't determine whether the person used gpg4usb and manually encrypted or if he/she used auto-encrypt. But what you can do is change the version to whatever the fuck you want and it will still work, as long as "version:" remains... for example, you can change it to this:
-----BEGIN PGP MESSAGE----- Version: this was not auto-encrypted
hQEMA9kpB4A18MYbAQf/YKN39d5TQDjKir/Yzu0D5uQjBLYaNRJz6mHuVqeCNAux lj4GIgIgWMVmrZUEU0BiTptnQA4IEPWX1H2IA7JIozAtqLZz/C38vfyqbO1f1d07 cJFOJVtgxqgMCFxrqfdwlNXAvw0PIwVHsFGIx67A+UCAbm8Ecb/CRVfG5NnbwwMM bgk8t6tSVl53nJnX2bj5INd1ohz6LEEYIYfw3lH6oBqrpcIADn4gwqPsjEim6Mu3 eJ1q4g2497wIBWxbEPtBLO5CHiAwNW5W0NQ3r7Yuc/Pj4KAfr5xwgw1iwpIgeqot tMvDvBN3yTzFHCcPmfTBFflFwRrZ/GJXBPpiWi3mMtI/AduQbEalYf4bX2/LgRhF ZIN3pLUAZHqpi0iWMysTMWPnhI7hN+vsB3YiFxOmPtj4g9rfujitFKbWX/N6CR3S =8gEg -----END PGP MESSAGE-----
By looking at the version now you can definitely determine it was not autoencrypted.
So what's the point?