What about the heat of the unit that AvCon mentions?

We mounted our unit on the yoke to provide for a more permanent
installation, and to eliminate the need to be looking down at your lap for
navigational information. (In my opinion, strapping the thing on your leg
is just goofy.)

With it on the yoke, there is no issue with heat, naturally. I would
imagine it would get quite warm strapped to your leg, since that big ol'
color TV screen generates a fair amount of heat.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"