Well, the VAT is usualy way more than the duty. The duty I've paid for electronic imported from the US must be very low indeed, because I didn't notice it on the customs papers. VAT though.. that's a pain.

As for customs officers stopping you on the streets.. nah. I don't buy into that. I know that if you cross the border with a car it's legal for a customs officer to stop you down the road a bit, but they can't just ask for "papers please!" in the street.