When you send out a copy request to libraries that work with copyright management, they will ask you to comply with their copyright management regulation. This may not apply to libraries in your own country, but, for example, most US and UK libraries do work with it.
If a copy request comes back to you with the answer Conditional - "Lacks copyright" you can choose to comply using the following steps:
The request will now go back to the lending library and they can supply the copy.
If you do not wish to comply, you can click the No button. The request will immediately go to the next lender in the Lender String.