They do not accept hyphens either! My first name is hyphenated ( Jo-Anna) and my passport contains it. Have cruised a lot And only once had someone question it at check in. HOWEVER, the main problem is with your Captain Club numbers or past cruising info/history. I have had to have accounts merged more than once over the last 20 years. You would think it would be accepted by now. It has been changed to Jo A or combined to joanna. Our last name is McGrath and have also had issues with a space placed between the Mc and the Grath!
But the check in should be OK and if not the supervisor always understands.
Otherwise, Love Celebrity, enjoy your cruise
Jo-Anna