There are a lot of laws that aren't enforced because they are outdated or just plain stupid. I didn't watch the video, however as far as my knowledge goes any Non DOT approved lighting or lighting modifier by the letter of the law is illegal and you can be ticketed for it. This is an example of the outdated or just plain stupid laws, the rear brake light flashers are a safety addition and most cops ignore it, however flashing red lights anywhere on the vehicle (other than rear turn signals) by letter of the law are illegal unless you are manually pulsing your brake lever (which I do at stop lights/signs and when I first start slowing down) devices that pulse the brake light for you are technically the way the law is currently written are illegal (except on emergency vehicles), but its one of those laws that needs to be re-written for new technology, the law was not written with the intention of blocking safety equipment but to make emergency vehicles easier to detect because they would be the only vehicles with flashing red lights so you could keep clear of them for safety reasons. The law was really only meant for light bars and the single round lights that volunteer ems/firemen use to get their personal vehicles to the station as quickly and safely as possible
That is my understanding of the way the law is anyway. I could be wrong and I apologize for babbling. I've been sick all day and I'm going nuts having been on the couch not being able to do anything all day today, one of the last nice days of the year too