I read on http://www.radiotimes.com/news/2015-03-30/heres-why-queen-elizabeth-ii-didnt-sit-on-the-iron-throne :
“Apparently the Queen of England [sic] is not allowed to sit on a foreign throne,” explained Benioff during an interview with Late Night host Seth Meyers. “This is an esoteric rule we didn’t know about until that moment.”
Is the Queen of the United Kingdom not allowed to sit on a foreign throne? If so, does that apply to fictional thrones?