One of the things I like the most about the iPad is its dedicated button to lock the orientation of the screen and prevent it from changing when we are in bed or lying down. However, after watching the first videos of the first beta of iOS 4.2, this button has the functionality to silence the iPad.
When the new firmware appears, we will have to block the orientation of the screen using the same process as on the iPhone, that is, by clicking on the icon placed in the multitasking tray.
Source: Macrumors
because on the iphone, the multitasking icon only locks the iphone vertically. I mean that looking at the iphone horizontally, you give that icon and it puts the screen vertically (this is like this the iphone). It seems to me a mistake, I think the current system is more functional. I hope it only happens in the betas, so you want to silence the ipad suddenly if it is not going to emit sounds.