Is it possible that within the required content section it displays the liveries required for a route aswell. There's one scenario I've came across and they don't have the liveries on their account but written in the description and for myself I am finding it difficult to find the correct author.
The only issue I can see with that is that liveries aren't technically required. It should be part of the options when uploading: 'Select recommended mod(s) for this scenario', and then the person uploading picks from the liveries uploaded on Creators Club. That way you can probably see who's trying with their scenarios as well. Of course, it isn't quite ideal but it means it's part of the process.