Indeed, the term used in EU bureaucracy is “posted workers”. It’s a mess described here:
https://europa.eu/youreurope/citizen…s/index_en.htm
@Free: main worry should health and accident insurance. Your employer must complete an A1 form, otherwise you may not be covered in case anything happens while working in other countries. If your employer DOES FILL OUT an For m A1, that is more than enough evidence that you were not in Switzerland. Of course, this only matters if someone starts to investigate.
k_and–e has it right.
So once again , this is not your problem, it is your employer's problem. What you need to do is to stress to your employer that you are willing to go wherever needed but not at the risk of losing your Swiss permit. Your employer has to figure out how to make that happen, while keeping permit, tax, and insurance folks on both sides happy.
Meloncollie's OH's situation closely resembles mine except for one important difference, I live alone in Switzerland.
Whilst I do not have ‘insight’ into the actual tracking of your passport/travel data at international airports by the Swiss passport control…
anecdotally…
my teenage son was accused (falsely) of a crime he did not commit (someone gave his name as theirs when caught) and the police contacted him and they were already aware that he was not in Switzerland at the time of the alleged offence. So they could see on the ‘system’ that he his passport/permit had been registered both exiting and entering Switzerland via the airport.
Your passport probably has a chip which stores all your essential data for travel. That is scanned every time you cross passport control at the airport…
EES tracks entry and exit through the Schengen area - which includes Switzerland -
https://www.sem.admin.ch/sem/en/home…reise/ees.html
And for any country where you work ‘on assignment’ your employer will need to ensure you are properly registered for legal work according to the local laws…