What's the deal with all the Nissan Almeras?

Over the last few days, I have noticed a strange trend on Irish roads. On a number of occasions a car has come up behind me, and then decided to drive behind me about a metre from my back window. I'm talking so close that I can see the driver's nostril hairs (eugh!). When an opportunity to overtake has appeared, I've slowed down to let them past (well, who wants to be rear-ended by someone driving so close?), but they just stay there. And here's the weird bit... They were ALL Nissan Almera saloons, and they ALL had their foglights on (no fog, of course). (Cue: Twilight Zone music...)