I could not tell due to the lighting where I was at, what the costume of the kid was.... and his father was standing nearby, so I asked him. He said he was "Bud Lightyear". Then he said , " I dressed up as one of the soldiers".
I hadn't really looked at the guy, Ok ... -10 points for me. But when I really looked at him, he was in some 'greens' and had an AR15 on his shoulder and a gun on his hip, along with a knife sheath and knife in it, flashlight, etc.
FYI, that was Buzz Lightyear. The soldiers are the green plastic army men. The characters are from Toy Story. I don't think they had M16s, so maybe his costume wasn't quite right.
Personally, I see nothing wrong with authentic costumes.