size matters.....
quad size doesn't matter,what matters is the size of package.Big packages attract customs officials easily.Lot of my products cleared customs without any duty even though the price was in the range of 150 to 200 USD as long as the package was small.
As long as your quad package is small and label doesn't mention 'drone' you are good to go.If your seller mention that 'drone' word anywhere on the shipping label chances of your quad seeing day light is none to non existent.