To answer both parents, the issue is gusting winds which can suddenly catch the brolly and invert it. This is a real problem, especially for cheap umbrellas. C

To answer both parents, the issue is gusting winds which can suddenly catch the brolly and invert it. This is a real problem, especially for cheap umbrellas. Clearly if the winds were a steady 60mph or so you'd never bother to open the brolly or if you had it open you'd close it to save struggling against the wind.