Grandma's never thrashed across the basement concrete, not like the slant Westy at home did on occasion. Hers was very similar model but without the timer, closer to BOL.
Not that it CAN'T go unbalanced, but you're standing right there and you can tell to stop and redistribute before it 'travels'. So a relative non-issue.
That's a mid-to-late 40's model, probably a '48, but to tell you the truth, in my many decades of Easy usage, I've never seen one walk about. I'll see what I can do, (smile).