Can it be detected if a unit has been rescued? Player1 has a few zealots, but there is also another rescuable zealot. After player1 rescues this zealot, player1 should still command the zealot, but it has to be detected as a rescued zealot.

Use bring? Rescueable player brings 0 guys to location, player 1 brings 1 guy to location, player 1 has rescued the guy. If you're trying to make the rescued zealot a hero zealot or something, you'll have a hard time.

No they are normal zealots. But player1 has to bring this rescued zealot to some location, only this rescued zealot and not another zealot.

Zealots outrun locations. The only thing I can tell you to do is detect when he's at a point on the map (say standing on a beacon) via EUDs.

Wait, so do you mean that zealots can run out of a location centered on it? Even with hypers?

zealots are the 2nd shortest units in the game. Much shorter than ghosts and marines. They have a 5-13 height. Zerglings have a 4-11 height. Firebats have a 7-14 height. All of them, in particular the zergling can move more than their top height in two frames (zealots and firebat can move 8, 12 when upgraded, whereas zerglings can move like up to 18 or something.