In the uncensored version, Yamcha left a corpse behind, and in Funi's he didn't... so it's possible Goku/Piccolo were just censored out. Because visible corpses make young children believe in zombies, or something.
I have no idea why Tien stayed there, though. Still, he'd been saying lines like "They're okay, I can see their parachutes!" when Nappa destroys the military jets in a scene that clearly has no survivors, and says "Just wait until it grows back!" when Nappa tears off his arm. He's like Funimation's Public Relations Officer. Back then, if Vegeta fired a Galit Gun on a group of puppies, Tien would be around to say "They're okay! I saw a group of happy orphans run in, scoop up the puppies and flee to safety just before the explosion!"
If kids thought Tien was actually DEAD, then maybe there were no parachutes! It's unthinkable. He's just sleeping, kids, don't worry!