Over at Slate, Josh Levin has a great article about the last time golf banned a putting practice, the "croquet" style, which was practiced by none other than Sam Snead:
The spry old-timer stands directly behind the ball, his putter between his legs. He then contorts his body into the shape of a question mark, anchoring the flatstick with his top hand and moving it forward with his bottom hand—an approach that golfer Jimmy Demaret said was reminiscent of basting a turkey. "I putt better this cockeyed way,” Snead explained to Sports Illustrated in 1967. “Not too many people can bend over quite as well as I can, but I think it is good for old golfers. They don't have to coordinate two hands, only one." And as he told the AP that same year, there was an additional benefit: “I can read the green much better with my croquet style because my eyes are so much closer to the putting surface.”
Before Snead got to stooping, the croquet crowd hadn’t attracted much notice from the USGA. But as Al Barkow explains in Sam: The One and Only Sam Snead, the straw-hatted, seven-time major champion was a famous name, a player whose actions could inspire widespread adoption of an unorthodox technique. At the 1967 Masters, the legendary Bobby Jones—a man who, according to the Atlanta History Center, “called singular attention to the game’s best traditions”—threw a conniption at the sight of Snead’s bizarro methodology. According to Barkow, “Jones sat with Sam in a golf cart and told him that the putting style he had adopted didn’t look like golf.” Jones mentioned his objection to USGA executive director Joe Dey, who “took up St. Bobby’s observation and set in motion the process of banning croquet putting.”
Despite the protestations of Snead, Gary Player ("I don't believe you should put a man down to hitting the ball one way") and Jack Nicklaus ("This is ridiculous. Why don't they just let us tee up the ball and play it?"), the croquet prohibition went into effect in January 1968. The new golf commandment both banned croquet-style putters like The Dude and decreed that it was henceforth illegal to straddle the ball on the green. “[F]or the first time in golfing history,” as Sports Illustrated explained in a 1967 feature, “the game's ruling bodies were telling a man how he had to hit the ball.” Dey told SI that a full-on ban “was the only way to eliminate the unconventional styles that have developed in putting. The game of golf was becoming bizarre. It was some other game, part croquet, part shuffleboard, and part the posture of Mohammedan prayer." Croquet putting had been banned, essentially, because a couple of old guys thought it looked dumb.