The problem is Nokia 5800,5230 etc has a button that you have to slide to unlock it so there is no chance of accidental unlock when the phone is in your pocket, and in Nokia c5-03 ofw you have to press unlock button and then touch unlock, here also the chance of accidental unlock is less as you have to press two separate place, but in nimble pro as only one button is required to unlock it the chance of accidental unlock is more.
in c0ntrary, slide to unl0ch is m0re like iph0ne, and for me i d0nt enc0unter accidentally unl0ck even while im w0rking and my ph0ne is inside my p0cket!