While I don't disagree, it's worth noting that any minor official at any airport -- and this very much includes the US -- has very, very wide-ranging powers over non-citizens traipsing through. Sample: https://en.wikipedia.org/wiki/Maher_Arar

Singaporean officials are also very keen on following the letter of the law, and in Singapore that letter happens to state that unauthorized possession of ammunition is a Very Big Deal.