That's a bit confusing as the constructor frigate does auto-use the ability (and it works for EA at least), but it's not visible on the unit's info-card - the player is left a bit clueless here.
As there's no ability icon to hover the pointer over, you also can't see the effective range of the ability - it's a bit "hit & miss" as to where to place the constructor so that it reveals the most mines.
Would be nice for the Delphi (and other races scouts) to have this, even if it required a tech to unlock the ability.
Edit: Shadow scout looks suitably scary - it even turns around like it did after the Whitestar first fired on it.
Vorlon "Light" cruiser - pray (I mean REALLY pray) that one of these doesn't turn up at your homeworld, it will be interesting to see what the younger races need to take one of these down. Nice ambient glow inside.
One Vorlon enigma though - after colonizing a planet both the colony ship & the constructor were both disabled - had to scuttle the constructor to begin building anything.