Factual error: In the beginning where John Travolta is going through the gates in his car, he stops to let the guard on duty see his military ID. Under the US seal it has the words "1ST Sarg." printed. Real military ID's would have "1SG / E8" printed on them where he has "1ST Sarg." printed. Also, his expiration date says "12/24/02". This would be printed as "2002DEC24".
Factual error: Throughout the movie the "HMMWV" being used in scenes are civilian Hummers painted green. They are easy to spot since they have 3 orange lights on the center of the windshield, where as military HMMWVs do not.
Factual error: Warrant Officer Brenner tells Colonel Moore "You have no rights to an attorney. You have no right to remain silent..." The UCMJ states: "Article 27(c) In the case of a special court-martial - (1) the accused shall be afforded the opportunity to be represented at the trial by counsel." "Article 31(a) No person subject to this chapter may compel any person to incriminate himself or to answer any questions the answer to which may tend to incriminate him."
Answer: It's just a generic funeral song and the bagpipes are supposed to make it more...mournful.