Haha yes I've had a similar scare a couple of times where I've nudged the handwheel when it's been sitting on my bench or the machine table, particularly when it's been set to x100. Now I have got into the habit of setting the axis selector to off when I put it down after each move.

The main drawback of the magnets is the buildup of vicious swarf around them when you've been machining steel or cast iron. But I like to park mine on the front of the cabinet when not in use, so to me the magnets are overall a useful feature.