Most modders mod games for themselves first and foremost. Sharing them is secondary, if we feel that others might enjoy our creations too. Enforcement of anything like this would just stop some from sharing altogether. Ultimately, it's the player who loses out while the modders continue to enjoy the fruits of their own labours privately.
I do like reading changelogs when they're available, just as I like to read patch notes for games I'm playing and this is why I include them - but doing such should NEVER be enforced. We're hobbyists. This is what we do for fun.