I've watched every video of this day and some of the others that were floating around from other days/times that people said were "lasers" too. In every video it's either an irregular reflection off a surface, light from filming equipment, or bugs. I think a lot of people don't realize exactly what a laser would look like in those situations. For example, the Weibo posts that made threats said they'd use a specific type of green laser. These are two 532nm green lasers in a lit room from the perspective of the target side. This is what SKZ/their staff would have seen had it been an actual laser, would be pretty obvious who and where they were, and they'd have been caught immediately.