The customer observed that there is a way to add a non-allowed content to ezobjectrelationlist.

Steps to reproduce:

1. Add "Content relation (multiples)" field to "Article" Content Type.
2. Set "Allowed content types" to "Article" and "File".
3. Create a new Article.
4. Select a content in ezobjectrelationlist to open UDW.
5. Select "create" tab and create content that is not among allowed content types (e.g. Folder).
6. Publish it and confirm the selection.
7. Publish the article.

Result:
Relation list ignored the fact that folder is not allowed and linked it.

Note:
In v1 there is a modal which says that content was created but couldn't be liked via relation list.