Did Elgiganten change how it works yet?
Just for fun I signed up. During the signup they say that by becoming a member you accept that they will send things via email etc, but its optional to accept this, you can still click the signup button but then you don't get membership status, you just get an account. Then on the kundklubb page it says that you are not a member, if you click join it will automatically enable email, sms and phone communication, but you can disable them.