Did it a couple of times myself when I had a silver Focus.
What's weirder is when I had my 156, people mistook me for a taxi an odd amount. Like a poster above, I was collecting a friend at the train station and someone got in the back:
Random bloke: "Hi, can you take me to X?"
Me: "Err, I'm not a taxi mate."
RB: "Oh, you look like one."
M: "No sorry, waiting for a friend"
He then sits there awkwardly for about 10 seconds, as if he's waiting for me to change my mind and suddenly take him to his destination for some money.
Another time I had a lady flag me down from a bus stop, thought she might need help so I stopped and rolled down the window, she ignores that and just jumps straight in the back:
Lady: "X please"
Me: "Oh sorry, I'm not a taxi"
Lady: "Then why you stop?!"
Me: "I thought you needed help"
Lady: "No, can you take me anyway?"
Me: "No sorry, I just live round the corner"
She then gets out huffing and puffing. I had to check my car after that to see if I'd somehow missed buying a taxi.
And I'm still yet to see someone using an Alfa as a taxi.