I was just wondering… how come some people know that they are coming to the championship?
is it just a guess, an assumption, or is there a way to get there without winning at the regional/chairman/EI/rookie allstar?

You can win the lottery (seriously)

On the first site there is a way to sign up for nationals. The cutoff to sign up is October I believe and you are not guaranteed a spot. Your chances are better if you did not attend nationals the year before because you can sign up earlier.

I have also heard of a way to sign up during competition weeks and first selects the best teams among the teams that request to do that but I am not certain on the details.

Hope that was helpful.

FIRST Hall of Fame and Legacy teams automatically qualify for the championships.
Not sure if FIRST still uses that rotating system that allows teams to pre qualify for the championships if they haven’t been there a certain amount of years or not.

The rules for Championship signup are found here:

Some people who say they are attending the Championship are going regardless if any of their teams qualify, in which case they’ll probably see if they can volunteer at the event or cheer for a friend team.

As for me, my high school FTC team is in its last year in existence and they qualified for the Championship, so I’m going regardless of what happens in FRC. (Though IMHO, 1714’s got a good chance of at least winning EI at one of their events, and 2791 has an outside shot…)