The first hotel I heard of doing this (flying the flags of its guests) was the Waldorf-Astoria Hotel in New York. They have a dedicated flag room with “over 190 flags of nations and corporations” so they may very well have the national flag of Burkina Faso. They also get a lot of heads of states and other dignitaries staying there, so they definitely go to the trouble of changing the flags for those guests. No idea if they do so for a salesperson from Eswatini or Estonia.