Since I keep my knives sharp, I also want to keep them - and me - safe. That means every single knife I own has some form of edge protection when it is not in use or in a rack or on a magnetic bar - no exception.
For most of my knives, I use simple extruded plastic slot style blade guards, such as these: http://www.chefknivestogo.com/knifeguard412.html They are cheap, easy to find, simple and most importantly, they work, I purchase them in bulk as commodities, and I have less worry about cutting myself if I am opening up a knife roll or putting knives away. I also make sure I enclose an appropriately sized one when I give a knife as a gift.
My experience is the simple plastic extruded guards are my best solution, especially when I am travelling with a knife roll.
Only for unusual blades, such as my extra-thick and heavy MAC honesuki, will I use the Victorinox Edge Safe or the LamsonSharp Blade Safe as shown here: http://www.chefknivestogo.com/knifesafeset.html It should be noted that the two names refer to the exact same product, but marketed under two different brands and names. I usually don't want to put knives into them if I can use the simpler extruded plastic guards, since the blade/edge safe is a Royal PITA when I put one into a knife roll. (for the honesuki, I should look at making a saya).
For all friends' knives which I am sharpening, I slip a not-very-expensive cardboard sleeve ( http://www.chefknivestogo.com/chblgu.html ) over the freshly sharpened blade, and then a small bit of painter's tape to tack the cardboard sleeve to the handle (so the sleeve won't quickly slide off when I return the knife) before returning the knife to its owner.
If a knife is going into long-term storage, then I am likely to use some sort of painter's tape on both sides of the blade to fully cover the edge.
I haven't bothered with the magnetic case - it seems to me to be overkill - and a lot more volume when I travel with a knife roll..
It's just careless not to take precautions. Doing those precautions and developing a habit to do so is just common sense.