But if someone tries to load it shouldn't it tell what assets are missing?
Yes. When you load one of my dufs, it will not find the morph and the character's textures.
Let's say I am trying to load Da Som Kim's duf, for example. This is the error you will get:
This is because I created a single morph for her, instead of just keeping the many different characters and such, and leaving it at that.
What I do instead is export the whole model into Blender and later import it in DAZ creating one unique morph to that character. This way I can uninstall anything that I am not using anymore and free up some disk space.
This is DaSom Kim's morph, it's just one single slider:
Another issue you will find is the character's textures, I save each of my character's textures in a different folder and name them accordingly. When I save the character's duf subset, I point all the body parts to these textures saved in that different folder. This is Kimberly's textures folder, for example:
In some characters it may ask for things like specific eyes, brows and such, which are things I still keep installed since I use them in almost all my characters anyway, so there's no reason to uninstall.
I still keep a lot of characters installed, like P3D Imogen, for example, which I use her eyes in 2 of my characters and there is an upcoming character I will use her as a base, so I just leave it installed, but if I see that the character will not need to be installed there forever, I just uninstall them.
So, in order to share my dufs, I would also need to share the morph file to be installed within the DAZ' folder as well as their textures, I don't remember which base model they come from since I just rename the files. So I can't even tell like, Alessa's base textures come from P3D Imogen or Julia is VYK Holland for example, because I seriously don't remember anymore.