...You would think if demo units had already gone out to a lot of YouTubers, you would see a lot more unboxing videos, or even first/initial thoughts. Anybody with an R5/R6 in their hands could rack up major views by throwing up a video about it this early.
Someone had to be first. I guess it was him.
I don't know what criteria Canon used to decide who would get review units and when they would get them. My guess, and it's only a guess, is that COVID 19 played havoc with the usual system, since they couldn't fly a bunch of reviewers to Hawaii or anywhere else and let them play with the cameras under their supervision.
Canon Explorers probably got pre-production units pretty early on so they could familiarize themselves and prepare promotional videos for Canon. I expect the most established review sites like DPR also got pre-production units a few days ahead of time so they could prepare their "first look" reviews.
Then, I suspect popular reviewers like Fro got production units on announcement day or the day after. Since he referenced the overheating issue with the fire extinguisher gag he obviously shot this after the first day, I wouldn't be surprised if he shot the video the day he got the equipment, beating others to the punch. I'm not sure how many U.S, reviewers are out there that have his following and are also entertaining and generally pro-Canon, so maybe he did a little begging to get special consideration. Don't know. Don't think it's important.