(CNN)Apparently, it happens more often than you might think.
Some people don't believe American flags belong on Confederate graves. Some feel so strongly about it that they remove those flags.
In one recent instance, however, the flag snatcher had a change of heart.
An unknown person removed 163 U.S. flags from Confederate graves at Shiloh National Military Park over the Memorial Day weekend. Staff discovered the flags were missing on that Saturday and replaced them in time for official ceremonies on Memorial Day (May 30), Superintendent Dale Wilkerson said.
The next day, custodial staff at the Civil War park in Tennessee found a bag with all 163 flags accompanied by a handwritten note.
"It was an apology that went on to express the person's feelings that American flags should not be flying over graves of Confederate soldiers," Wilkerson told CNN on Tuesday.
"But history teaches us that they do belong there."
Some who hold the Confederate cause near and dear aren't so sure of that.
'Put a Rebel flag on a Rebel grave'
It's not obvious whose side the flag snatcher was on. The Shiloh battlefield, which is in Tennessee near the Mississippi border, was the site of one of the bloodiest Civil War battles, leaving 23,746 casualties in April 1862. Today, it's home to five identified burial trenches, the final resting place of thousands of Confederate dead. Federal soldiers are interred in the Shiloh National Cemetery on the battlefield.
"People need to understand that American flags are out there as a sign of respect, not disrespect," Wilkerson said. "It's a sign of respect for those American soldiers."
A post on the park's Facebook page titled "Why There Are American Flags on Confederate Graves" laid out the events that led Congress to recognize Confederate veterans as American soldiers, according them the same benefits and honors as American veterans of other conflicts.
Whoever took the flags may have been "mindless vandals," the post said. Or, maybe they just didn't know that "over the past 150 years Confederates have come to be considered American soldiers."
Not everyone sees it that way. Responses to the Facebook post reflected the growing divide over the Confederate legacy in modern America.
One commenter claiming to be a descendant of five Confederate soldiers said he took offense to the American flag being placed on Confederate graves.
"Yes they are considered American soldiers but that isn't the flag they [fought] under. Placing THAT flag on their graves is nothing more than a slap in the face!!!!!!" the commenter wrote.
Said another, "Use some common sense. Don't put a Yankee flag on a Rebel grave. They [should have] been taken off. Put a Rebel flag on a Rebel grave."
A minority felt equally strongly about according Confederate graves the honor of the American flag.
"Who considers these men American soldiers? Whoever does is mistaken. These men voluntarily renounced their citizenship and took up arms against the United States of America. Judging these men to be American soldiers is certainly not the consensus opinion in the United States," another commenter said.
Michael Landree, executive director of the Sons of Confederate Veterans, said there is nothing wrong with a "50-star flag" on a Confederate grave.
But, a Confederate flag "would be more appropriate," he told CNN.
"That's the flag they fought and died under," said Landree, who retired from the Marines in 2015 as a lieutenant colonel. "We don't disparage the use of a U.S. flag on them, but a more appropriate flag is a Confederate flag."
Not the first time
NPS regulations (PDF) allow for the placement of small Confederate flags at federal cemeteries on two days: Memorial Day and Confederate Memorial Day in states that observe it. Members of the local Sons of Confederate Veterans camp held a memorial service at Shiloh battlefield on May 30 and decorated the burial sites with Confederate flags with the park's permission, Wilkerson said.
"I don't think this is an organized effort by a group. It's just some folks who don't quite get why the flags are out there and feel compelled to take them down."
Because those are the only times Shiloh decorates the graves, those are the days the flag-snatchers tend to show up, Wilkerson said. This was not the first time, and he doubts it will be the last, but that won't stop the park from putting them up.
"It's our honor to place those flags out there," he said.