It has been a while since security asked me to bootvup the computer; many use the "sniffer" method now.
In the past, I would put the laptop on sleep mode and if they did ask me to boot it on, I press a button, the NT login screen come up instantaneously, and I would be waved through. I am not too concerned about battery life since since I don't work on the plane (or much off the plane

).