I expect they have strict guidelines, and thats based on the law. They do take a tough line but so do other countries. The many instances of this that I see on Border Security, NZ, OZ, Canada show this. I just out it down to a heavy emphasis on employment being lost to imports. But I feel that they don't have much discretion as they have to go by the law. If its very marginal, they can show discretion but the aupair stated she will be working. I take it that its taking the hard line, to A) comply with what the statute states, and B) to draw a clear line. We see many instances of discretion when it come to food items. Some get fined, some get a warning. I take it that employment is a big deal