It would be useful to have a "List" access type in Windchill that sits between no access (completely hidden) and "Read" access (can see attributes and viewables) for those cases where customers want users to know something is there but not see any content of it without further permission.
There was a community discussion on this topic that presented the scenario of being able to check to see if a number is being used before creating an object of that number and not being able to see this, at least not until getting far enough to face a ID conflict.
I have another scenario where users spin their wheels because they think there is some system error or they are entering information incorrectly. Users learn that it probably means they do not have access, but sometimes it really means the object doesn't exist.
A "List" access type would allow a user to see the File Name (for CAD), Name, and Number of an object, and perhaps other key attributes such as Revision and State, but not see any other attributes of the object and definitely not access attachments or representations. Basically, they are allowed to see that such content exists so they know not to create a duplicate or don't spin their wheels thinking something is broken or they are doing something wrong. Either way, user and support time and frustration would be reduced for situations where exposing these basic attributes is acceptable to a business.
A List access type would allow companies to decide to keep content absolutely hidden (understandably sometimes even confirmation of the existence of something can be a breach of security) or allow some set of users to know something exists and take appropriate action. Addition of this type would allow this control within the normal Windchill access framework.