It's the kind of thing a competent A/V staffer would think of because the event's insurance would have required more credible sourcing. Given the nature of the crowd, I wouldn't be surprised to learn they had no legal support or insurance.

Yup, never ever buy lasers / UV light equipment from Amazon. Shit's dangerous and they don't go through any real regulation.

You often get class 3B lasers being sold as 3R which is extremely dangerous. I opted to pay a lot more for a green laser for astronomy purposes on a legit website then buy dirt cheap on Amazon because I don't want to blind/injure myself or others.

Which is why you hire an AV company to put on an event like this, and not just pay Bill to show up with a truck full of electronic crap.

related: https://youtu.be/CpRMud6EFtE