So in any event let me make sure I understand this:
If you take a picture of someone (say their portrait) they do not have to do anything to release you the copyright...
You own the copyright to a photo you take automatically on pressing the shutter. The model has no rights over the copyright (unless you sign a contract to the contrary). However there are countries where that is not the case in all circumstances*.
No. A model release is nothing to do with selling the photograph it is to do with using their likeness.
You can make a print of the portrait and sell it for money without a release.
You can put it in a photo book and sell it without a release.
You can even sell it to Coca Cola for them to use in their advertising without a release.
However Coca Cola can't USE the image which shows the persons likeness in their ad campaign without a release.
Likewise if you wanted to use the portrait in an advert for your studio, in your local paper, you would need a release.
Also, if you gave the image for free to a charity (no monetary gain) they can not use it to promote their cause without a release.
It makes no difference if they do or don't sign a release. The model/subject has no right to use your photograph in any way at all, unless you grant them such rights in a license agreement. The copyright in your photo is totally separate from their right to control the usage of their likeness. Just because they appear in the photo they don't have any right to make use of it.
*Australia is one such place.

