Yes, what a shame it would be if Boeing made public comments about something being investigated by the NTSB... Oh wait they did [0] and the NTSB decided not to kick them off...
> The agency stopped short of restricting Boeing’s access to its investigation ... In some previous cases, the NTSB has gone so far as to throw participants off an investigation for violating its rules. In December 2010, the safety board removed American Airlines Inc. from an investigation into a runway accident in Jackson Hole, Wyoming, two days earlier.
So many keep quoting this but I fail to see how exceptions prove rules. In fact they contribute to disproving whatever it is that they are an exception for.
I believe the original meaning is more like if there is an exception, there must be a rule (otherwise it wouldn't _be_ an exception/you wouldn't need an exception). It's been watered down a lot, and is often used to suggest that any counterexample makes a rule stronger (which is obviously not always the case -- enough counterexamples just proves the rule is wrong/doesn't exist).
People misuse it a lot. Sometimes they're implying that if you can only find a handful of counterexamples, then you're showing how strong the rule is overall. Sometimes they're just spewing nonsense.
The original meaning goes like this: an exception of "if it's Thursday, you're allowed to have a brownie" proves/implies a rule of "no brownies"
> The agency stopped short of restricting Boeing’s access to its investigation ... In some previous cases, the NTSB has gone so far as to throw participants off an investigation for violating its rules. In December 2010, the safety board removed American Airlines Inc. from an investigation into a runway accident in Jackson Hole, Wyoming, two days earlier.
[0] http://www.heraldnet.com/business/ntsb-scolds-boeing-over-78...