Is it appropriate to offer guests of a surprise birthday party to chip in financially for an upgraded air bnb?

I am planning a surprise birthday party for my husband. He asked for a cabin rental at a fairly nearby popular mountain area in the past, so I am doing that. I invited his best friend and his spouse who are out of town saying it was my plan to rent an air bnb for a night. I was just asking if they would be interested and they immediately said yes and purchased a plane ticket within the same 10 minutes of my asking. There are some places I can rent that could accommodate us all but they are not that nice. There are considerably nicer places for not much more, that I cannot afford on my own. Would it be rude to make the offer that if they want to get a nicer place I would need them to chip in?