I'll say it as many times as I need to: USFSA does not tell the judges to "send messages" to skaters. Some of the judges on the committee may have their own opinion of skaters that reflects their job on the committee, but a lot of judges are simply that: judges. They go to the competition, sit down, judge, and go home. The most feedback they get from USFSA about their judging is something along the lines of "you gave that element a +2, based on the bullet point system it should've been 0 or in the negatives" or something similar.
Therefore, I think that any score dropping is less a message from USFSA to tell skaters to retire and more a message from the judging panel that the skater needs to do something differently. That something differently may be a response to the packaging, mistakes, performance quality, skating skills, losing jumping ability, etc. The skater can choose to work their butt off to correct those problems (like Adam and Mirai), decide they want to continue for love of the sport rather than competitiveness (Rachel), or simply retire.
If USFSA does send messages, it's through direct communication, not scores. Assignments may send some kind of message, but for things like the Grand Prix they don't determine assignments. We know they'll tell people who may not be internationally competitive in singles to switch to pairs or that they sometimes suggest partnerships for dance and pairs. One would think they have discussions with certain skaters about their prospects for that season.
@Seerek As I pointed out in another thread, after Spring 2011 Rachel Flatt went to Stanford. I think Freshman year she was seeing how internationally competitive she could remain, but in the years after that she was skating for fun and love for the sport - not because she thought she'd be on the World podium. I'm sure USFSA knows that, and I'm sure the skaters tell USFSA stuff like that. Not that they'd turn down international assignments or teams if they made them, but that they are skating because they love it as opposed to training all-out for an Olympic medal.