My friend keeps telling me he is “target farming locks and mirrors”. Is he correct or wrong?

This sounds silly to ask but maybe I’m crazy. Haven’t played in a while since affliction league but my friend says he is using a certain rogue strategy to target farm locks and mirrors. This sounds incredibly dumb or am I wrong? It’s RNG right?

He found 2 locks in 20 maps. Then in 30 maps he found another lock. No mirrors yet just 3 locks in 50 maps total. How do I tell him he’s wrong and you can’t target farm these you only increase the currency, density, etc by juicing.