Not only do you have to give notice, but here in Norway you also have to include employee reps and follow a strict process. Part of that process is to define criteria for how to determine who should stay or go. Then after notifying the employees about the ongoing reduction, each employee should have the opportunity to discuss with their superiors how they fit the criteria or if there are other roles in the company they could fill. And then at a set time the actual layoffs will be announced.

So it's virtually unheard of to show up, hear about layoffs, and not have a job the next day. Unless it's a situation where the whole company is going bankrupt or so.