I think that a standard needs to be established to make this topic viable. No team that was eliminated in the first 5 episodes should be considered because they had minimal opportunities for screen time. Any team in at least 6 episodes can be considered. Using that standard, here are the teams that I think qualify for minimal screen time:
A team I think were nearly invisible was Aja/Ty in AR13, where they made it to episode 5 (Cambodia). They lasted though South America with little screen time, then their problems in New Zealand were not highlighted until the end when they got a slim victory over Marissa/Brooke. The only leg where we saw much of them onscreen was Siem Reap and throughout that episode we knew they were doomed by the flight schedules before they were actually eliminated.
Another team qualifying for the "invisible men" were Andre and Damon in AR3, who made it through 6 episodes before being eliminated in the 7th. There was the hassle by the police in Casablanca, followed by their not making it past the Paris airport that night. I then remember them sleeping on the train past Innsbruck, but that hardly mattered since they were already incapable of getting out of last place and elimination.
A third team is Karli and Kami in AR5. They made it all the away eastward to New Zealand in episode 10. They were visible swimming across a short patch of water to a tiny island off Bahia Lopez in the Bariloche area. They had a difficult time loading the sheep and goats into the felucca for the voyage across the Nile River. Their decision to not go for the Amazing Race flag cost them about 45 minutes and bankrupting in the Dubai sky-diving, but they were non-eliminated. Other than these incidents, I do not remember seeing them on the AR5 telecast much.