Line of sight

In the book, it simply says you have to be able to draw Line of Sight to the body of a model to target them.

I played an opponent last night who claimed line of sight to one of my units because he could see under the legs of models (cavalry) of an intervening combat.  They clearly could not see over the models and were on a level field from the desired target.

Basically, LOS went right over the bases of 2 separate units with lots of models, no exceptions.  Was I right in asserting that he could not see through my models? 

For times sake, we rolled for it and ended up letting him shoot counting as Hard Cover (not too much effect on WE way-watchers).  I seem to remember that a model is considered to take up it's whole base.

Using true line of sight, all you need to do is draw a line from his eyes to your model's body. If he can do that, be it through the legs of a hundred tap dancing savage orcs in top hats, then technically it is legal. I find that since you can never actually get your eye exactly at the height of the model's eye it is very hard to agree on the really crazy LOS shots. A laser pointer often does a better job.