The reason a patient (brand new to a practice) can register without making an appointment is based on a balance of the process flow of the existing practice management systems and enabling identification by the practice of new patients.
The process follows that a 'new' patient must first register into the system and then once registered, they can make an appointment. We find (in our practice and others) most patients register and make an appointment immediately after the registration process, however some patients register and make their appointments at a later date. We have had to follow the process this way as it minimises the risk of anonymous 'new' patients booking into your practice without any trace of contact. At least this methodology allows you to contact the individual patients if need be because they have had to submit a minimal amount of contact details.
This could be for a number of reasons such as cultural backgrounds or for example if they have come from the UK where they do have to 'register' with their local practice. We have a number of international student families in our area and some of them 'register' one day but make their appointments several days later.
This is the balance between enabling 'new' patients to make appointments at your practice and potentially building your patient base or we can disable the 'new' patient access and only allow existing patient to make appointments