The "I have the right to distribute . . ." checkbox comes and goes with the tide.
After reading this very old post, it seems it works depending on what uploader you use.
https://www.boonex.com/forums/topic/I-have-the-right-to-distribute-these-Sounds-.htm
It's there if you choose the Regular Uploader and disappears if you select HTML5.
May I ask, what is the logic behind that?
As I need it and I'd like to use the HTML5 loader, can some kind person tell me how to get it back?