According to a German website Macerkopf, there is a possibility that iOS 5.1 will enhance Siri with the ability to control the hardware aspects of your device. Which means, when you say so, Siri might take a picture or shoot a video from the camera in your iPhone 4S.
This means that Siri might control your camera and may not switch of the Wi-fi when you ask it to. These speculations are going on due to the announcements and rumors that with iOS 5.1 in your iPhone 4S, you would be able to ask Siri to take pictures, shoot videos and switch on/off Wi-fi in your device.
It is also being said that Siri API might allow users to issue commands to third-party apps and accessories.
However, we advise the readers not to allow skepticism creep into their minds before seeing the actual product as Macerkopf is not considered a reliable publication when it comes to report news on Apple products.
Source: 9 TO 5 Mac