Actually come to think of it, this wouldn't be the case for a lot of people.
If you're able to do everything that you would do in 8hrs in a 6 hour working day and assuming you're being paid by the day and not by the hour then you'd also not be liable for a lunch. I work in IT so working lunches at my desk are a regular thing which doesn't bother me and I'm sure a lot of you are the same. The big issue however is that companies would be see their employees doing 30 hour weeks instead of 37 and thus would expect to only pay them for 30, even though the output is the same.
I think it's an interesting topic but Sweden is a special case for not being as full of greedy assholes as other countries. It's pretty funny, when you're working in England as long as you're at work no-one will judge you. You spend 2 hours at your desk looking at pictures of cats on the internet? No-one cares because you're at work. But if you spend 2 hours doing that at home you're branded as lazy.
Social stigmas are great