How this works:
Your email address and password are combined then 'hashed' to form a unique id.
This is done in your browser, your email address in plain text never leaves your phone or computer. (If you prefer
not to use your email address at all, you can).
Due to this you do not and cannot receive email notifications from submitting your email address on this page.
Assuming you used a strong unique password, it is virtually impossible to go from the hash alone back to your
email address.
However, people still may be able to reidentify you, especially those who know
your whereabouts or people you handshake with.
This is Open Source and so you can check
the source code or "View Source" in your browser as it is only HTML and Javascript.