The float test would disallow many fabrics currently used in all sorts of clothing, even cotton. How long does the testing have to run while waiting for the cloth to saturate and sink? The manner in which the cloth is placed in the water can determine how well it floats. I can see all sorts of arguments come out of that. Next I suppose they'll be testing swimmers for "slicking agents" like Teflon. I seem to remember sailing competitions that inspected boats for dispensing systems used to make the water-hull boundary layer slicker.
As a father of a competitive swimmer, this rule will really help out my pocketbook if he progresses far enough. Those suits are very expensive.
And really, a buoyant suit? Heck, why not make the suit in the shape of an inflatable boat and put a jetpack on the back while you are at it? This isn't the America's Cup where the technology of the boat is an important part of the competition. It is swimming.
They should have a 'float' test. If the swimming suit floats on top of the water, it is banned.
Cycling went through a similar phase when recumbent bikes were first allowed, then banned after smashing every known record. It's really arbitrary at what point you disallow technology advances in judged sports like swimming for the Olympics.