I agree there is no right or wrong aswer so the only thing you can judge on is simply your own feeling/instinct and information you collected from experience or studying everything you can find on the topic. Like @t_h_wyman said, if all or at least most already piped in the same egg box then I think I would get nervous about the last ones that are not open yet and cut them. They at least had the same circumstances, incubation time, almost same temperature ect. And I would still cut only a small cut enough to get it started.
But finally you can indeed not see in the egg, so whatever choice you make, you really never know on that moment if you made the right choice. To cut can kill the snake, but you might also be a lifesaver. Only one thing I know for shure. I would only cut if the others that pipped where in the same eggbox. A friend lost last year four banana het pied girls because of cutting. He divided the clutch between two smaller boxes and didn’t notice that the temp in one box was lower than the other what resulted in them developing slower. In the top box almost all hatched. So he cut the last ones both boxes which ended up in killing all the babies in the down box. It was so sad to see. Also because of this I would not cut untill at least most in the box pipped.