[paydevs]

Completely agree, no developer of an open-source software has explicitly stated that a) his software is open-source and b) that he adheres to OSI's definition.

Most developer just uploaded their project to GitHub and attached a license. If OSI defines some licenses as open-source or not is irrelevant. Legally only the license is binding.

[mfts0]

I agree that it doesn’t make sense to let some institution define what open source is.

In the end for open source to be open source it should be publicly accessible.

Anything else should be defined in the license as the maintainer/creator wishes.