The poster was phenomenally successful, and no foreigners dared to live in Switzerland in case they got shot at. Remember that all Swiss men carry knives and guns.
Despite being heavily armed at all times, the Swiss stayed neutral during World War 2. The SVP, famously opportunistic, used their marketing genius to turn the war to Switzerland's advantage with a series of posters along these lines:
Cash flowed in from all round the world, and especially from Germany. However, while the SVP were happy to grow rich on foreign coin, anti-immigration sentiment remained strong.
Economic necessity led to the first trickle of immigrants since the Habsburgs. In the mid-fifties, there was a grave shortage of expressive body language in the German-speaking parts of the country, so tens of thousands of Italians were shipped in. Rates of gesticulation increased by an average of six percent per annum.
After the Italian wave came a whole bunch of guys from war-torn Yugoslavia. The Swiss were annoyed by this until they realised the 'Yugos' would give the national football team some decent players.
The most recent trend, and the most troubling, is the flood - of biblical proportions - of Germans. Switzerland has a population of 7 million, and about 3 million of those were born in Munich, Stuttgart, or Berlin. They eat currywurst, click their fingers at waitresses, and refuse to learn Swiss-German. The Swiss are crying out for a latter-day William Tell to drive away the invaders.
But until such a hero announces himself, the SVP will have to make do with a new poster campaign. The message is clear - There's nothing we want from Germany: