The poker in Maverick wasn't quite as authentic as it wanted you to believe
The real “Hoyle’s Games” book never actually mentioned five-card stud.
The classic Western series Maverick intentionally bucked (no pun intended) the usual Wild West tropes. Creator Roy Huggins wanted a hero who was smart and resourceful instead of the usual rough-and-tumble tough guys that lead many cowboy movies and TV shows at the time.
James Garner played Bret Maverick, an intelligent man who would rather beat someone at cards then with his fists. Many times, though, his gambling got him into trouble.
In the third episode of the very first season, titled "According to Hoyle," Maverick falls for a con set up by the beautiful and conniving Samantha Crawford (Diane Brewster). She convinces Bret to play five-card stud exactly by the rules stipulated in the book Hoyle’s Games. He agrees, thinking he knows the rules well enough. Crawford eventually wins the game with a pair of nines even though Maverick has a straight.
She quotes from Hoyle’s book, "In five-card stud poker, straights are not played unless it’s determined at the commencement of the game that they be admitted." Maverick admits that no such agreement was made and gives up the pot. A fan favorite, Diane Brewster played Samantha Crawford in three more Maverick episodes.
A title card at the beginning of "According to Hoyle" stated: "The Rule of Hoyle quoted in this story is authentic, and is from Hoyle’s Book of Games, 1876."
In reality, though, that’s not the case.
Edmond Hoyle lived in 18th-century England and wrote many pamphlets on the rules of games like whist and backgammon. After he died in 1769, publishers used his name to convey rules of many different games. In fact, "according to Hoyle" became a common phrase not just for referring to the rules of a game, but used any time someone wanted to do something properly.
There was an 1876 edition of Hoyle's Games. However, the closest thing in it resembling modern poker is something called "Bluff." Straights are not referenced so technically Samantha Crawford is right, but there’s nothing about five-card stud or establishing certain rules before playing.
Of course, no one ever accused classic western TV shows of being historically accurate. They wouldn’t be nearly as entertaining if they portrayed everything, well, according to Hoyle.