@puffinus_puffinus@sunbeam.city @tastytea
This is, simply put, anti-ethical.

Since it is supposedly a scientific study, I would suggest contacting the review board of the university (or something like that).

Participation in scientific studies is not something trivial. Usually it is necessary to get a signed form with free and informed consent; implied consent should not be acceptable. And both the allowed uses and the handling of the data are very restricted.