In both single-player and multi-player, creative mode and survival mode, Iron golems will spawn to protect villagers. However, people may make square boxes with water draining to the center, and put containers with villagers on each side to 'spawn' iron golems and have them fall like with a normal grinder.

This is a problem with multi-player servers as they are able to produce a doublechest of iron ingots in just a few hours - and this is a form of exploiting (producing an infinite amount of iron ingots, just like how sand/gravel factories made infinite sand/gravel).

My suggestion: either remove them from dropping anything like with the snow golems ... or have them just drop roses since they do that anyways. Please consider this - ekl