No – the data is encrypted in the QR code, so that this is hindered. When you scan the SecTrace pass, a few selected details of the data are visible for verification. For example, after the scan you will see the initials, the entered zip code and the last 3 digits of the phone number. This data is intentionally not printed on the SecTrace passport.
So you can ask your guest for one of these 3 details to make sure that he uses the right passport. (The rest of the data is of course encrypted and cannot be read out to ensure privacy).