[Tuidjy]

Ich, the slave collar was used back in Dominions II. Actually, it was done with
some other item... It was just remembered as the "slave collar trick" because
some people think that a slave collar is the best item to use.

I disagree. Depending on your objective, it may be better to use a worthless
item that you can remove, i.e. store on your commanders until you need to flood
the enemy's lab. Otherwise, you compromise your own forging one turn before.