Where did all the Danish flags come from?

This is a question that several news stories and bloggers have asked lately. For example, from Charles Moore in yesterday's edition of The Telegraph:

It's some time since I visited Palestine, so I may be out of date, but I don't remember seeing many Danish flags on sale there. Not much demand, I suppose. I raise the question because, as soon as the row about the cartoons of the Prophet Mohammed in Jyllands-Posten broke, angry Muslims popped up in Gaza City, and many other places, well supplied with Danish flags ready to burn. (In doing so, by the way, they offered a mortal insult to the most sacred symbol of my own religion, Christianity, since the Danish flag has a cross on it, but let that pass.)
Why were those Danish flags to hand? Who built up the stockpile so that they could be quickly dragged out right across the Muslim world and burnt where television cameras would come and look? The more you study this story of "spontaneous" Muslim rage, the odder it seems.

I suspect the answer is that they were home-made. The flag of Denmark is not difficult to make, and if you look closely at some of the news photos, such as this Reuters photo from Pakistan, it is fairly easy to discern from the slightly misaligned cross that this one was run up on someone's home machine.

Others such as the ones in this Reuters photo from Turkey, have a cross that is centered on the flag. Denmark's flag has a "Scandinavian" cross, which, like those on the flags of Norway, Sweden and Finland, is set off toward the hoist of the flag. The centred cross on these flags technically make them flags of the French province of Savoy.