You should be fine. These days I have not seen anybody asking you to
turn on anything to demonstrate system's safety.
Nobody's asked me to demonstrate anything post 9/11. I've had an external HD in my laptop case for years--it's never been looked at one bit.
Pre 9/11 I was a couple of times asked to turn on my laptop and I've had security people look through the viewfinder of my SLR. (And had a bit of hassle with one who didn't believe my camera because she couldn't see anything through it. Of course you can't when there's no lens attached!)