I did not see any kind of security mechanism for the Joycons at events, they were just constantly monitored.
There's nothing really wrong about that at events, but will stores employ workers just to keep guard on people trying out the Switch? That could be very costly, maybe too costly for a single displayed console.
Not sure if it's common practice to have an employee constantly watch over a displayed console. In my country displayed consoles are hidden somewhere in the display box under a LCD display and their controllers are attached to a power cord that is also some kind of safety lock and no one really watches over them, since they can't be easily stolen.
I imagine the Switch being attached to a safety mechanism similar to how the PSP was displayed, but I'm not sure how they'll attach Joycons to safety locks.
Discussion started at here by ninja1635