My guess would be that other nations would not recognize the LoMs and consider the privateers pirates even on the high seas. Unlikely they would pursue them unless they were engaging their flagged vessels. However, most of the piracy and such is happening in territorial waters even if in international straits. As such, any entry by an armed vessel would be most likely met as an act of war and most certainly would be a violation of the Law of the Sea. Even barring that, I would suspect that a privateer would not be granted entry into other nation’s ports or would be subjected to import regulation on their arms and possibly be denied innocent passage through territorial waters since they would be armed but not “warships.”

As for Presidential control, a vessel operating under an LoM would need support of US bases and would need export licenses, all controlled by the President.

In short, since the bureaucracy has reached every nook and cranny of the globe, they’ve taken all the fun out of it.

According to Wikipedia, “[i]n 2004, Military Sealift Command civilian mariners were integrated into [the Mount Whitney's] crew. She remains a commissioned warship in the United States Navy, but the size of her complement shrank from 600 sailors to approximately 170 Navy officers and enlisted and 155 civilians.”

From an efficiency standpoint, this looks like a home run. The ship is able to perform the same functions, but the complement was reduced from 600 to 325. The Navy needs to do more of this.

This may be picking nits, but the C2 ships are still technically commissioned Navy vessels. Mount Whitney, for example, is still the USS (not USNS) Mount Whitney and doesn’t have a “T” prefix on the hull number. You raise a good point, however, which is that the complement consists of 170 Navy personnel and 155 civilians. While I expect that many of these civilians are higher-end technicians, I don’t see any reason why, on any Navy vessel, the more mundane tasks in the laundry and galley need to be performed by Navy personnel. Turn these functions over to civilian contractors and focus the Navy personnel on the core war fighting functions.