Many people in the market talk about the prediction market's end-of-session strategy making small profits regularly, but losing it all when encountering a black swan. There are also many who discuss the YES + NO arbitrage, but these are all old players who have not truly run the strategies themselves.

1. End-of-day strategies cannot be mindlessly all-in; with so many events in the market, a true end-of-day strategy is to diversify into the end of day. Additionally, event selection itself is not simply about jumping in when seeing a 99%; there is room for strategy optimization in deciding whether to sweep the end of day.
2. YES and NO themselves are shared order books, which means that with a dual taker strategy, it is impossible to buy YES + NO < 1. It is only possible to buy YES + NO < 1 through a Maker + taker or Maker + Maker approach, which is called a market maker strategy and has nothing to do with arbitrage.