Either the market is open or closed, and when that changes is a very well-known schedule (for the most part). Even the US stock market would run into some very unhappy people if they partially closed a market (e.g. only allowed buying, not selling) or they closed a particular stock at their whim.

I'm not saying this wasn't risky or dumb, I'm just saying the US stock market is a poor counter-example because both of the things that happened in this case are exceedingly unlikely to happen on the US stock market.