@Debbie106
Hi Debbie - probably nothing to really worry about - but on principle it isn't right. I have heard of several guests opening more than one profile - mainly to 'qualify' for the $50 travel credit Airbnb give out for referrals. Of course this is cheating, and if you feel strongly enough about - when your guest checks in - ask to see her ID and later, after the booking is completed successfully and you are writing her review, mention it in the section where Airbnb ask if there were any issues about the guest. And you can always 'flag' the other profile and report it to Airbnb.
Best Wishes.