Originally Posted by
GUWonder
But indeed the lack of knowledge about the potentially applied laws/regulations can cause issues. But even for those who work in this area, it's usually targeted to see a transit stop for this, and it's rather infrequent.
You're right that the practical aspect of the rules is very important as well (which is why I have mentioned how these controls work in practice in post #2 ).
The issue is however to say point blank that there aren't any controls when transiting into the Schengen Area. The OP or anyone coming here for advice will be led into a false sense of security. The trouble with customs rules is however that not declaring may be construed as actively trying to avoid payment of duties and taxes.
That is IMO why it's important to indicate the theoretical rules as well. There's no point in arguing with the customers officer ("well all the other don't do checks) if you're stopped because the customers officer won't care how other colleagues are conducting their job.
Not to mention that these rules may work favorable to the traveler. If he's transiting through a Schengen member with lower taxes than his final destination, he might save a couple of bucks.