I wonder why the author used two parentheses in the sentence below:
While touring the Center for Agrobiotechnology at Monterrey Tech, its director, Guy Cardineau, a scientist from Arizona, remarked to me that, in 2011, “my son-in-law returned from a tour of duty in Afghanistan and we talked about having him come down and visit for Christmas. But he told me the U.S. military said he couldn’t come because of the ((State Department)) travel advisory here. I thought that was very ironic.
Is there any special rule regarding parenthetical statements? Isn’t one set sufficient?