Why would TWO border checks be performed for the same bus upon entering Switzerland?

Question

Yesterday I went by bus from the Euroairport (French sector) to Zurich. Unusually, two Swiss border checks took place.

First, at the St-Louis border checkpoint, officials boarded the bus, asking foreigners (including me) where they were going, for what purpose and for how long, and collecting all passports for scanning. This check took 30 minutes.

10 minutes after leaving the border, the bus stopped at the scheduled bus stop in Basel, where a mobile team of officials boarded with portable passport devices. They scanned all passports and visas and checked entry/exit stamps. Myself I was asked where I was going, where in Switzerland I live, for what purpose I live there, where I was travelling from and for how long I'd been there. This check took 15 minutes.

How come the same authority (the Grenzwache) would check the same bus twice, given that no passengers can get on/off the bus between the border and the bus stop in Basel?

Answer 1

There cannot be and will not be a fact based answer. However, this question can be asked for a lot of security/border checkposts etc. E.g. Why do you have to go through security check again at some transit airports although you had a securtiy check at you origin of departure? Why are sometimes multiple security checks at airports?

The answer is always the same: It increases securtiy or it increases the feeling of security. The first possibility is most of the times the "official" one. However, to my opinion it is most of the time the second possibility which is the "real answer".

So for your specific case. Switzerlands oficials can now state that they 1) control the border and 2) control (maybe randomly) buses/trucks whatever within the country. Or that they increased the controls.

Is it somehow unlogical to control the same bus two times? Maybe yes, however you postulate that the controls are for the pure purpose of the control itself and not for political reasons (=feeling for security). Still you might argue, that a double control is always more save than a single on, in theory the bus can of course stop between border and basel and get more/less passengers etc.

Regarding the question of JonathanReez: Since June 12th 2017 there are systemic border controls between Germany and Switzerland because of the "refugee crisis" (source in german, just translate the second header)