Tighten legal language in Disclaimer: avoid unverifiable copyright-ownership claims

README.md

@@ -41,7 +41,7 @@ size_categories:
 
 This repository is **not** an official release of SPA-Data.
 
-SPA-Data was created by Tianyu Wang, Xin Yang, Ke Xu, Shaozhe Chen, Qiang Zhang, and Rynson W.H. Lau, who retain all copyright and intellectual property rights. This repository does **not** claim ownership of any images or metadata.
+SPA-Data was created by Tianyu Wang, Xin Yang, Ke Xu, Shaozhe Chen, Qiang Zhang, and Rynson W.H. Lau. This repository does **not** claim ownership of any images or metadata, and attributes the dataset to its original creators. (We describe them as "creators" rather than "copyright holders" deliberately — copyright in academic datasets can rest with an author's university, a funding body, or otherwise, under arrangements we have no way to verify from the outside. The official repository's BSD-3-Clause license, discussed under [License](#license) below, is what actually governs redistribution here.)
 
 This repository exists for two purposes: