Well, when handing in everything today (woohoo!), my teacher glanced through it and said that when she marks it, she's going to try and get every possible mark from it. The procedure as far as I know for our school is that a few courseworks are selected at random and moderated. If too many marks are being given (or perhaps too few?), then all of the courseworks will be moderated, and be re-marked as such.
For a subject like Art, internal marking is probably quite biased - giving as many marks as possible without the moderators having a problem with it.