I'm curious if the DQ on the 400IM was on the Start or the Turn?!
I'm not an Olympic Gold medalist nor a a collegiate official, but I don't know why you can't call that?! I'd have to see the video. At the SEC Championships... are they using 2 Officials per side (in other words each watching 4 lanes) or one per lane?
On the start, you are transitioning from Back, which is a finish on the back. It would seem to be a very clear and easy call.
Go to the 2:15 mark of the men's Olympic Trials...
http://www.youtube.com/watch?v=5nJHF_AELVcI don't see any turbulence, bubble...
This one is the actual Men's 200IM Olympics... at the 4:35 mark is the transition:
http://www.youtube.com/watch?v=GTbbnhnnMQUIt provides the underwater view... which shows all of the swimmers submerged through the dolphin kicks (ie no bubbles). True the water isn't still... but it should show that an Official standing directly above the lane should be able to make the call if a 2nd dolphin kick were taken.
Now the frequency it is called and the strictness of the official...