Hi,
@bvdveen : If you set the option "registration" to "no registration" in the hikashop configuration, the registration form will still show BUT, the username/password fields are removed and when the user enters his address, and click on register, no account is created for him. If that's the text which is bothering you, you can change it with translation overrides:
www.hikashop.com/en/download/languages.html#modify
@SG : If you keep the login open turned on, you can have the people login with their login while still being able to not create an account after having them enter their address.