It cuts both ways is the way notice periods are viewed in Switzerland. There are legal minimums that can be increased but not decreased. These are 1 week in the probation period which is a maximum of 3 months, 1 month in the first year, 2 months in years 2-9 and 3 months thereafter. Resigning before starting is permitted in law and for the company this entitles you to 1 weeks salary and for you this entitles the company to reasonable expenses. Given that they very probably had a short list which you topped, the reasonable expenses are none. If of course you resign a few days before starting, they might be less well pleased. However you can offer to turn up and work a week and then there is nothing they can do - and they are very unlikely to take you up on your generous offer. If of course, you simply do not turn up you might get a shock...