After careful exploration of the only correct design the whole is stable and will remain so, unless you rude and gruff deal with him. For department stores and the like it is, therefore, not suitable. But otherwise - when treated with respect they (gently moving and Gently adjust) - it is quite usable. Some stabilizing elements and fixing possibilities (eg the "chassis") would have a favorable effect on the stability. Attrition, crack and bending I have not noticed.
