"A様がおられますでしょうか？" : Isn't おる 謙譲語?


I heard a very polite employee say to a customer over the phone:

> A様がおられますでしょうか？

Most people would say いらっしゃいます instead of おられます.  
The use of おる here surprises me because I have been told it is 謙譲語.

Is it a mistake, or some advanced usage, or something else?

