As an amateur vexillologist, I was delighted by vonCube's writeup, Flags of the World: A Style Guide, and was even able to offer a small addition by referencing one of the many stolen, burgled, and pilfered flags hanging in my living room. It is in the spirit of petty larceny and good drinking stories that I offer you this:

Stolen Flags of the World: A Larceny Guide

I attempted to categorize them in some meaningful fashion, but unfortunately the only category that any of them fit into was "stolen to assuage petty personal grievances". Instead, I will list them in alphabetical order of the entity which they represent.
  • Afghanistan, National flag of the Islamic Republic Of

  • I stole an Afghan flag from a group of ANA who were too chickenshit to guard their own corner of the FOB I had to share with them. As far as I was (am) concerned, if they aren't brave enough to defend their own flagpole from enemy attack, they aren't brave enough to have a nice flag to put on top of it. The converse logic was (is), if I have to defend their flag for them, I'm going to keep it when I leave.
  • Croatia, National flag of

  • There was a Croatian motor pool with a very tattered, very un-serviceable (by American standards) flag hung out front. Naturally I was affronted by this and decided that it would look better hanging in our planning hooch preserved as part of a coalition historical display.
  • Finland, War flag of

  • Finland has a "war flag", which differs from the normal state flag in that the Nordic cross carries a state seal in the center, and the leg opposite the pole is tapered. This particular example is a swallow-tailed version.

    Some pretty rough Finnish dudes thought it was funny to keep stealing our butt can, since it was right outside our compound gate. So in turn, WE thought it was funny to steal the flag off of one of their APCs, and put it on an improvised flagpole right inside our compound gate, a spaced steel grating, so it was visible to the Finns across the way.

    That's good ol' fashioned American escalation of response.

    They kept stealing the butt cans, though, until we threatened to steal the rest of the APC. I asked one of them later what the hell they were doing with all of those butt cans (they must have had ten of them) and found that they had been using them to mark off a corner of their own compound as a designated smoking area/trophy case.
  • Germany, War flag of

  • The Bundesdienstflagge, also known as the "war flag" when flown by the Bundeswehr (German Army), is the German national flag with the iron chicken (federal crest), in the middle.

    This was actually my second "war trophy" from my stay on a shitty European-run FOB. The Bundeswehr did, and didn't do, quite a few things that left me very unimpressed with their... how can I put this... unimpressed with their martial spirit. I was able to steal the flag right off of their HQ building because they were too drunk to notice me simply walk up and take it. Keep in mind, this is at a FOB in Afghanistan, and the sentries guarding their command section were too drunk to notice me walk up to within 20 feet, untie the line, and pull the flag down. You can imagine how much help they would have been if the shit had hit the fan.
  • Poland, Variant flag of

  • The variant or state flag is the same as the standard, but is defaced by a state crest in the upper, white half.

    The flagpole outside the Polish compound at one base had, literally, fallen over. The ground was so soggy from three solid days of storms that a good wind came along and pushed over the flagpole, concrete base and all. The flag sat on the ground for a day and a half before I liberated it, figuring that either A) nobody had noticed, or B) cared if they did.

    Apathy is the greatest aid to burglary.
  • Prince of Unnamed Middle Eastern Country, Personal flag of

  • Unnamed Middle Eastern Country is cool with letting us move through in transit, and even allows us to operate a small staging base, on the condition that we don't publicize it or cause any local issues. It's a "keep it on the downlow", weaselly diplomatic situation.

    The problem is that the new (at the time) snotty little prince who'd taken over the job of head of the port authority/customs department thought himself to be a "better Muslim" than the rest of the family/government. And, while he couldn't stop things entirely, he did make our lives very, very unpleasant for a few weeks until he got his peepee slapped. There's no doubt his bullshit had a significant impact on operations. So natch, we stole his personal flag off the port authority building while he was visiting the facilities we were stuck in.

    It was easy - the guards were on a break, drinking tea and picking their toenails (seriously). So, minus the guards the only thing stopping us was the cyclone fence of the holding pen, a single line of concertina wire, and a ditch.

    The problem was the size of the flag. It was too large for one person to conceal, so we ended up having to thread one end up one guy's right sleeve, the other end up one guy's left sleeve, wrap the ends around our torsos, and walk out the front gate of the facility holding hands.
So, next time you find yourself dealing with an uncooperative, surly, or mischievous sovereign entity, you can collect the bill on their debt of honor by stealing their sovereign symbols. They make great living-room decorations, and if you get a matched set, you could make some pretty kickin' curtains. The Prince's flag is too big to hang up, but lately I've been considering turning it into a quilt.