Alright, so here's the skinny (though I'm no expert, so take everything with a grain of salt).
As far as I know, the Wiz should not interfere in any way with the plane at takeoff or landing. It just shouldn't be a problem at all. Period. HOWEVER, I would suggest not using it during those times. They'll probably hassle you if you do.
NO YOU WON'T GET ARRESTED, so there's no reason to freak out. You would likely have some flight attendants ask to please put the device away.
Also, mobile devices aren't restricted because they pose some sort of threat of bringing the plane crashing down. That's not the issue. The reason the flight crew asks people to put mobile devices away during takeoff and landing, is because there is a chance that they can cause radio interference. And of course, the pilot must keep clear radio contact with the control tower to get "the go-ahead" (if you will) to land or to get instructions on whether or not they need to re-route. If there is static and interference, there's a chance the pilot could misinterpret/misunderstand/mishear crucial information, and attempt to land the plane before it is safe to do so.
But don't worry, the chances of interfering with the radio are slim anyway. Everyone who says it could interfere with the actual plane engines/computer hardware, etc. is just yanking your chain.
Have fun on your trip though.
Oh and remember, turbulence is a common occurrence and is perfectly normal, so just try to stay calm if that happens.