I agree that mobility aids are extensions of the body of the person with a disability. That's a very important message that, unfortunately, is not sufficiently passed on to those staff members who handle those mobility aids.
There's no foolproof solution. Right now, aircraft are not necessarily equipped to transport those mobility aids in the cabin, which would be perhaps the perfect solution, although it may be an aspiration to move in that direction in the coming years in terms of engineering and what may be safe and possible.
What certainly can be done in the short-run is to impose a very significant, automatic and immediate financial consequence of over $100,000 per each incident that happens. Once there is a high price tag, the airline will work much harder to prevent that type of financial consequence.