No, I know another great trick either you phone is on airplane mode or what ever !! but you need to be on jelly bean for this trick, well the trick is while your device is locked down and you think you've forgotten the pattern lock or pin and your data connection is also in switched off !!

and you seem to get

then hold the power button and a popup will appear asking switch off, data connection off or on etc, if you data connection is off in that menu it would be enable data connection, and once you enable the data connection you a open your locked down device with the help from your gmail account. See, it is not that tough to you can get your self out from the lock down issue, you just need to remember while you locked out press the power button so the popup will appear !!
