Depends if they can Google your name or any identifier you gave them and find something. Not just Google, but also their internal tools. They can ask Facebook: is this email address associated with any Facebook account? How about this phone number? Those are two things you need to provide on your visa application.

Funny, but my e-mail address IS associated with Facebook account, but it is not my account. My e-mail address is very popular among some demographic who doesn't understand concept of e-mail, and, as a result, associated with tons of accounts on all services which don't check e-mail with code or link. booking.com, for example, but it is only most visible and funny :-)