There are other ways to lock your BlackBerry screen besides the keylock icon

When I am storing my BlackBerry in my pocket and I don't want my device to record unintended number-calling keystrokes, I hit my home screen's keylock icon.

Yet as AllBlackBerry.com points out, you can also use keyboard shortcuts to lock your device.

"On Suretype devices, like the 7100 or the Pearl, you can hold down the “*” key and the device will lock, AllBlackBerry.com points out.  "On Qwerty devices like the 8700, hold down the Alt-key and the Enter-key.

There's also the option of setting your BlackBerry to automatically lock when you holster the advice. That'd be Options, Security, General Settings and set the Lock Handheld Upon Holstering to "Yes."

And finally, if you've placed a password on your BlackBerry, please remember it. If you enter your password incorrectly as you try to unlock your device, ten incorrect guesses in a row will wipe out your BlackBerry.