As a side note to any fan who may have been at that game (or any other, I suppose), when two players collide, and maybe even one or both get hurt in some way, this is NOT always a foul.
You need to keep in mind that soccer is a contact sport. This particular game was very physical, and yes, there were a fair share of fouls, but not every single slide tackle nor collision is a foul.
Regarding the red card that Coach Carson mentioned above, my child was even closer to the action on that one than the coach, and their recollection of the event is the same. The two boys got tangled up, the Summerville player was trying to pull his leg free, and boot might have hit face - I guess a lot depends on your angle.
Many people didn't see what caused the Summerville red card in the box, and I imagine most fans had no idea what rule infraction caused the WA keeper to be awarded a red. But you can bet they let the ref know how bad he screwed up on both occasions.