This last week I had a bunch of newly purchased cars come in with flat tires. Two only had 2-3,000 miles on it, and my last car on Friday only had 200 miles on it.
The repair order said there was a piece of metal in the tire, and they were right. More specifically, it was a padlock key. I dismounted the tire to check how big of a hole it had made, so I did a full plug-patch instead of the usual plug.