The copyright-owner can choose any license they wish to. But if they decide to choose an open source license (lets say Apache 2), how much do they have to conform to the license? Especially, do they have to release the source code somehow (or make it accessible for whoever got the binaries that claim to be Apache-licensed). Or is it just a false claim, that it is open source, if the source isn't available?
Software isn't inherently licensed in any particular way. Rather, it is released under a licence; which licence or licences it is released under are at the discretion of the copyright holder. That there can be many different licences under which a piece of software is released should make it clear that the licence isn't an inherent property of the software.
A copyright holder claiming that their software is open source is making a statement with no real content; it can't be right or wrong, for it is meaningless.
If a copyright holder claims to have released a piece of software under an open source licence, but they have not in fact released it in this way (or at all), then they are wrong - because of the lack of a release, rather than because of a mis-statement about an inherent property of the software.
From Apache version 2.0 (emphasis mine):
- Redistribution. You may reproduce and distribute copies of the Work or Derivative Works thereof in any medium, with or without modifications, and in Source or Object form, provided that You meet the following conditions:
- No one is obliged to redistribute anything.
- Even if they do, they don't have to supply the source.
And even with more restrictive licenses like GPL, point 1 still applies.
Additionally, you have to keep in mind that the copyright owner can distribute his project under whatever license they please to different people.
What this means is that you can release your project to people under an open source license and to no one else. And these people are in turn under no obligation to redistribute the project. In the case of Apache you can even make sure the actual source never sees the light of day (I believe).
Putting that aside for a moment though, if you claim that your project is open source and no one can get a copy of the source code, what you're saying is, though perhaps technically correct, incredibly misleading at the least and likely not going to sit well with many people.