Tad,
That's because it seems to be a tradition only in certain parts of the country, and mostly for the big monohulls. It is normal for all classes, large and small, at local clubs on Lake Erie, as well as at their Inter-Lake Yachting Association regattas.
And PLEASE don't use the word "brag" -- that's probably why Jake doesn't fly his flags all the time, because he is too modest and humble and doesn't want people to think he is "bragging" by flying his regatta flags.
I wish I could find my pictures to show you of all the big boats at Bay Week flying their flags at dock. It is truly a sight to behold.
One minor problem is that flags are highly coveted. Several years ago our Hobie 18 was on the front lawn of the club as always during Bay Week. We had three strings of regatta flags on our boat. When we came to the club the next morning to race, our flags were gone. We were devastated, because, as I said, this is like our family history of racing (sort of like the old lawn chair is for the Key Largo Steeplechase).
Well, we put out the word about this loss, and we got our flags back. Turned out that a drunken crew member on one of the big boats had taken them. One of his fellow crew members saw them in their cabin and shamed the guy into returning them.