I think what they are saying is that the levelers only have a one year warranty (reportedly), so if they fail after that period the owner must repair or replace at their expense.
I suppose it can be seen as a safety issue, but so are worn out tires or brakes. When they wear out it's up to the owner to replace them before it leads to an accident. In these cases there is no "backup".
In the case of levelers, I think they could (should?) all have retraction springs so as to keep them up off the road when the hydraulic cylinder or valves leak.
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