Yeah.... it's not impossible for them to actually delay the Justice League.
Let's say it just about makes 800m worldwide, and with awful reviews, with the meh word of mouth, with the meh legs. It would be a disaster..... and Snyder have to be let go. There's no way WB could put a positive spin on this.
All assumptions at this point, but I suspect WB will checking the box office every day for the next 3 weeks pretty closely.