I can't speak to Washington law, but I almost had to sue someone in small claims court. I did not have to notify them until after I filed. Then, I would have had to get someone to serve the notice. I had the paperwork filled out, gave them one last call before I left for the courthouse, and they asked me to come by so they could give me my $1700. Guess they knew it was a loser and didn't want to have to pay my court costs.
I don't think they have to notify you until after they file.