Weirfan The USGA cannot tell us hackers what we can and cannot use , thats why we have illegal ball, hi cor drivers, square grooves etc being played every day.
Well, they can and do, obviously. When a person plays golf, they do tend to 'play by the rules', as far as they know them in some instances. When a tournament is played, the rules are the rules of golf. I've yet to play in a tournament where there is a different set of rules.
When I buy equipment, I'm always aware of what is 'legal', and tend to purchase only that type. I do own the newest (supposedly) illegal No Brainer head, but I did not buy it. I used it during 1 round, and found it to be a farce. I do not record rounds for handicap, but I still make sure I go on the up & up.
If I play a round, and happen to break Par, or have a HIO, how am I to brag about it if I did not use legal, certified equipment/balls? So, what the R&A/USGA set up as the rules, has very much an affect on me and my playing. I'm certain I'm no exception.