Hi Scorpion and others
It would be an excellent resource particularly for users that restore older machines. However, the main problem with this is copyright.
> depending on the presence or absence of copyright notices ...
It doesnt make any difference if there is a copyright notice or not - the manuals are automatically copyrighted to the company that made them and permission has to be explicitly obtained to have them available for download. For instance as soon as you make a photo or make a book or short article, i.e. any creative work, the law is that copyright exists for that work. You dont have to apply for it or register it. Placing a copyright notice on it is good practice but not necessary.
Hence the problem for the admins is that they would need to contact the companies and get permission.
(Technically people should have permission for all the little images on this site of coffee machines but common sense tells the companies that its effective advertising.) Copyright also allows the use of images or material such as manuals for the purposes of criticism or review. But an archive of them for the convenience of users or keeping for posterity is not an allowed exception under copyright law.