Use common sense. An experienced pilot should know what the limits are of their craft and be aware of the conditions they are flying in. If Yuneec says 20 mph, and you're out flying in measured 20 mph wind, then suddenly up where it can't be measured there is severe gusts/wind shear causing loss of control, should Yuneec be responsible?
I routinely fly in 20 mph when over Lake Huron without worry. I don't with the P4.
Common sense says don't fly during a typhoon, but Ming did it to prove a point. I certainly wouldn't. Know your limits. It isn't Yuneec's responsibility to spec out every last possible scenario that could happen.