Non UK Passport Hotel Supplement

Hi,
I was looking to book a holiday next year and one of our Turkish friends was going to stay with us. I have noticed when looking at various hotels that they state that there will be a supplement for non UK passport holders. Does anybody know anything about this as I am presuming it would affect my friend. Any advice would help as we don't want to turn up at a hotel and she would be refused entry (which seems bizarre anyway!). If there is a supplement does anybody know what it is so I could let her know. She says she doesn't know anything about it.
I was looking to book a holiday next year and one of our Turkish friends was going to stay with us. I have noticed when looking at various hotels that they state that there will be a supplement for non UK passport holders. Does anybody know anything about this as I am presuming it would affect my friend. Any advice would help as we don't want to turn up at a hotel and she would be refused entry (which seems bizarre anyway!). If there is a supplement does anybody know what it is so I could let her know. She says she doesn't know anything about it.
