Makes perfect sense to me. Pond snails reproduce fast, their egg cluthches are tiny making them hard to find, but contain many eggs. And where there is one, there are more. I think they may be pne of the snail species where even one can produce more. Assassins work well, but I would be suprised to find they won't take a nerite down if hungry. They take down juvie Spixi snails that are larger than an adult nerite. I would combine them with the finger method (smash one ones you see, they run slower that way).