I don't think that would qualify as explicit consent. According to GDPR consent would have to be: "freely given, specific, informed and unambiguous indication of the data subject's wishes by which he or she, by a statement or by a clear affirmative action, signifies agreement to the processing of personal data relating to him or her."

How could "anything you type into our forms may be captured" be construed as a clear affirmative action by the person entering data into the form that has a submit button for submitting the data?

Also, to make it unambiguous and informed, it would at least have to be a very-very obvious statement, which would make it useless for the sneaky purposes, wouldn't it?

Edit: I know it's not only GDPR that is being discussed, but I think would follow the same definition.