I hope that everyone who's currently saying that you have to add a header to avoid Google's FLOC thing realize that the header won't have any effect unless you're serving ads, right?
For the Origin Trial they are running it only includes your domain if you run ads in the first place
This is plainly documented in the Github repo
gulfie 
@ChlorideCull It's not going to hurt to add the header to though, and frankly I wouldn't be surprised if Google changes their policy on this
@gulfie It's going to hurt if the header changes in any way as the spec isn't finalized, but because "I already blocked it" people don't change it, and thus end up with it unblocked by the time they actually need to block it
They are unlikely to change it for the origin trial, as things are far from locked down in terms of how the opt out/in would even work in practice - right now you can effectively opt out from producing any meaningful data and still use the FLOC IDs, which means ad providers would cannibalize each other.
