Aah, the old "nudge them in a direction so when they figure it out they think it was their idea" trick. Very effective; but it takes a degree of trust in your subordinates (namely that they're smart enough to figure it out given enough time).

Anyway, if you take your primary job as a manager to be building your team's skills, it's absolutely the right way to go. People tend to remember lessons they learned the hard way, so I like to let my people fail in small ways because it's instructive.