A neighbour of mine uses one of the many telephone services available for low cost calls. This particular service offers international calls at certain times for a fixed monthly cost. I don't know the exact terms of her particular option, but basically she can make unlimited calls between 8pm and 8am for the one fixed fee. You can find all the various options on their website: www.ono.es
Her latest bill arrived, and instead of just her usual fixed monthly charge, there was a list of all the calls she had made outside the pre-determined hours of her service - all in the hour or so before 8pm. Now, knowing that she never makes international calls outside those hours, she called the company to protest. After much aggravation trying to get to speak to a real person rather than a robotic answering service, they admitted that the error was their's, and was due to the fact that they had "forgotten" to adjust their clocks when daylight savings came in a couple of weeks back. The calls have been refunded, naturally.
I for one don't believe that this was an accident. Was she the first and only customer of theirs to notice this error? Have they now notified all their other customers of their error and issued refunds? Do they not operate a computerised system that automatically adjusts the time? I know my bog standard, off the shelf piece of PC junk can and does do so, so why not theirs? I personally believe this was just a cynical ploy to fraudulently charge customers for services they had already paid for, in the knowledge that the majority will not bother to check their bills and will not notice.
The moral of this little tale is clear. Check all your utility bills carefully. Check your bank statements. Check your receipts from supermarkets and other large stores etc. Recently I have personally found stores such as Carrefour, Leroy Merlin etc., putting one price on a product on the shelf, but charging you a different price (higher, naturally) when the product is scanned at checkout. Occasionally this could be a genuine mistake, but it seems to happen all too often, and most people will not even notice.
Watch out! You have been warned.