It depends on the country and the time period. There were stretches of time in Poland when being caught with a substantial amount of foreign currency would have meant heavy jail time (for the crime of 'speculation'). But no one in history has ever gone down for having too much hooch.
I'm talking about Yugoslavia and 80s. Borders were officially quite tight (you couldn't import anything beyond some small value), but lots and lots of people used illegally traded foreign currency to buy food, clothes, toys, computers(yes, you could not buy zx spectrum in Yugoslavia), etc. and bring it illegally over the border.
It is likely that things were different in 70s and even before that, because rules relaxed a bit in the 80s.
They went down on not paying income tax on the proceeds of selling that hooch. If they just had it in a closet somewhere, it is doubtful that the government would ever find out.
That's how they got the higher-ups in the organization, but lots of people were arrested for simply having it. That's what allowed a black market to form in the first place.
