Originally Posted by Merlino
If your trousers have belt loops you MUST wear a belt.
I will concede that trousers without belt loops might be the ideal choice for wearing braces. However, since in theory one ought to be wearing a suit jacket anyway, and that jacket ought (again, in theory, and often in practice) to be buttoned nearly all the time, one's belt loops would not normally be visible.
Of course, neither would the braces be visible. Many people fail to understand this fact, that when worn with a suit, braces are akin to underwear. Invisible to public scrutiny.
Admittedly, some men choose to wear braces without a suit coat, and their braces - and belt loops, if present - are visible to the public. But their mistake is more properly one of failure to wear a jacket, than it is the wearing of braces with trousers having belt loops.
It's like stating that it's wrong to wear boxers with pictures of The Great Gazoo on them, if you're attending a formal wedding. Unless your boxers are on public display, there's no problem. And if your boxers are visible, the issue is more properly that you're showing your boxers in public, not that your boxers feature a cartoon character.