In some German drugstores, it is now normal that customers are only allowed to buy a limited number of milk powder packets a day because of hoarding behavior. Even at German airports, it is not unusual to see empty milk powder shelves in drugstores - thanks to the Chinese, who stock up in transit. But imagine that you were suddenly only allowed to go shopping in the city once a week. That's what it's like for people in the southern Chinese city of Shenzhen.

The shopping paradise of Hong Kong is only 30 kilometers (20 miles) away. However, last Monday the government in Beijing announced that in the future Shenzhen's inhabitants would only be permitted to go to Hong Kong once a week.

Until now, mainland Chinese had been allowed to visit the island city daily, even as individual tourists. According to estimates, this will reduce the number of visitors in Hong Kong by nearly 5 million people per year.

On their shopping trips, people don't just buy clothes, watches and jewelry, but also daily necessities such as milk powder, cosmetics and medication. Many Mainland Chinese distrust the quality of products at home. And Hong Kong enjoys the image of having many Western products and quality products to sell. Last year more than 47 million tourists visited the city; in 2013 there were just over 40 million.

Border trade should be restricted

The new rules are not directed at tourists, but instead at cross-border trade. Statistics show that overnight tourists are more interested in luxury and leisure than in drugstore shopping. The main target of this new rule is the smugglers who travel daily to Hong Kong to buy cheap goods and sell them for more money on the mainland.

For a long time now, locals in Hong Kong have not been amused by their continental neighbors' shopping excesses. The Hong Kong government is now planning to build shopping centers on the outskirts to relieve the center.

China's crisis can't be all that bad if Beijing can afford to limit consumption in Hong Kong to relieve the people there. However, the government's concern is probably not for Hong Kong, but rather stimulating consumption on the mainland.