Chinese Air Marshals are nice guys
In China every flight has one of these guys on them (at least one) and unlike in the US they are not incognito. They all proudly wear belts that say "jingcha" (police) on them and they always sit in the first row of the economy cabin in the aisle seat. They often have the whole row to themselves and on crowded flights if you ask nicely they will let you sit in the window seat of their row with the middle seat empty. Sometimes they even offer without any prompting.
I hope that their US training doesn't teach them to become donkey wipes like some of the US air marshals.