I have read many stock related forums over the years. One thing I have seen many people say is that they refuse to use stop orders because they don't want the market makers to "take out their stop". There seems to be a widespread belief that because stop orders go to the exchange, the market makers can see everyone's stop orders, and they will sometimes manipulate a stock's price to trigger a large amount of stop orders and obtain people's shares. Quite a few people have lamented that their stop order was triggered at the exact low of a move, and then the stock immediately started moving up again without them.
My question is do market makers really try to trigger people's stop orders? If so, how does that benefit them, and is that type of price manipulation even allowed?