I do have a quick Prague Metro story. Upon arriving in Prague, Matt explains to me that the Prague Metro does not check tickets and that it essentially operates on the honor system. The tickets are rather cheap though--about 50 cents--so we buy them anyways. When we get to the ticket machine, there are 10 different ticket options. Since we were only going 2 stops we figure the cheapest ticket would be sufficient. We ride in a similar fashion for the first day or so.
The next night as we're exiting one of the metro stops a man approaches Matt and starts saying something. Now, I should mention that being approached by random people in Prague is not an unusual thing. While walking around town, people would come up to me and ask or tell me all sorts of things: "we have the best beer!" or "a new stripclub just opened up", etc. So when this guy approached Matt, Matt just kept right on walking. Finally, the guy corners Matt and whips out this little keychain fob badge. Turns out he was a Metro official and wanted to see Matt's ticket. Thinking nothing of it, he shows the official his ticket. The official looks at it, then looks at Matt, and it's at that point that I walk up to them with a confused look on my face. Seeing me, the official asks for my ticket as well. I present it to him and then he proceeds to explain to both of us that we had purchased incorrect tickets and that we were both required to pay 500 Krowns immediately.
500 Krowns is about 25 dollars.