Fred,
The IRS is not "trying" to define the meaning of being outside the US or not. The have their definitions set in stone and have an all out effort to target all flight crews in the US and outside the US. Being outside for the presence test or the bonafide resident test is one thing. Being outside for determining the source of your income is a completely different issue. Even at the state level the efforts have started; California and Kentucky are vigorously trying to tax air crews that are based and/or fly over their territory for state income tax.
The hiding comment is directed toward reporting all your income, regardless of source or type; if you don't, and the IRS comes after you, you will be wide open for penalties, back taxes, and perhaps a visit to the can. If you have reported all your income and get audited, even with the bogus "international waters" issue, chances are you will owe nothing back, there are simple ways to beat the IRS at their game, just takes a little effort and a big cup of coffee. Been there done that.
Only thing that might help is if you voted for the current guy in office; socialist democrats get a pass on the tax cheating...