> Switzerland is in Schengen and they kept border checks all the time

Not sure "all the time" is accurate. Two years ago I drove a car through Switzerland, entering from the South border and leaving at the North border (and ~3 weeks later, the opposite way), there was no border checks at all. The only control we encountered when traveling from Spain to Sweden (and vice-versa) by car was the quick checks at the German<>Denmark ferry border.

It's not "all the time", but any time they want. You have to declare goods all the time though (if above limit) as there are limits in place for meat, alcohol etc.

> You have to declare goods all the time though (if above limit) as there are limits in place for meat, alcohol etc.

Yes, of course, but this is true anywhere, not just for the places under the "Temporary Reintroduction of Border Control".

I live here 15 years and cross borders to France and Austria quite often. Of course not 100% of the checkpoints are manned 100% of the time, I know quite a few small ones around Geneva for example where you could smuggle truckload of heroin 24/7 for a decade without any worry of ever seeing border police. Also checks are random and not focused on specific things, sometimes romanian van chock full of stuff is stopped and sometimes its swiss family car.

But all major are and were in the past, all frontaliers coming daily for the jobs in all border cantons can tell you about wonders of morning checks corresponding massive traffic jams forming in front of the border crossings, every single day. 1/3 of my office colleagues experience this every day.

Major eastern border crossings are 100% manned though, morning day night doesn't matter.

Given they're not part of the EU, and you have to pay import duties and VAT, that makes more sense than Poland/Germany.

Schengen applies to people. However, Switzerland is not in the EU and, crucially, not in the EU Customs Union so there are import limitations.

They do not check extra hard, though... It's been a number of years but they used to wave cars through or even have border/customs checkpoints closed depending on their 'mood'...

Of course actually seeing those border checks is another thing entirely ;)