@Katie195 If your Instant Book setting only requires an Air BNB profile, then you will get "newbies" who have sketchy profiles. That does not necessarily translate to scam or bad guests. Since you already have the booking, I suggest you send a message asking for details about the guests and about their travel plans. If you don't get a response or a response that bothers you, you can cancel the booking by stating that you are not comfortable with the guest.
Meanwhile, you should either get rid of IB or use the criteria that requires a guest to have at least one positive review before IB can be used.