anything can be smuggled, so long as it is not declared
common items include rare and endangered species, non-native species (smuggling across quarantine boarders) etc.
of course now in this wonderful police state we live in that is post 9-11, even common garden fertilisers can be smuggled, because they contain nitrates etc. which are incorporated into explosives...
it would be considered smuggling so long as you do not declare the items through customs, and whether or not you are later charged (if of course you are caught beforehand) depends on the amounts and the nature of the undeclared items (now-days even aerosol deodorants need to be declared before boarding an air-plane... and no nuts or food-stuffs are allowed into Australia... but these would more commonly only be confiscated, rather than leading to an arrest)
