I think it's required to take laptops and videocameras out of their cases for the x-ray. In-Out-Off:

Quote from TSA:
Keep available your airline boarding pass and government-issued photo ID for each adult traveler until you exit the security checkpoint.

* Place the following items IN your carry-on baggage prior to entering the screening checkpoint:
o Mobile phones
o Keys
o Loose change
o Money clips
o PDA's
o Lighters
o Large amounts of jewelry
o Metal hair decorations
o Large belt buckles
* Take your laptop and video cameras with cassettes OUT of their cases
* Take OFF your outer coat, suit coat, jacket, or blazer.