Answer
** Internal Publish Only! This article may contain information that is not intended for external circulation. **
Beta permissions on the Customer Care site are similar to EDN. It is not a role linked to a customer number but a permission assigned to the global account. The way it was explained to the CSRs in training is that beta 10.1 follows their global account wherever they go on the Customer Care site. If they are in beta for customer #10 and are viewing customer #12 on the Customer Care site, they will STILL see 10.1 beta info for customer #10 because it is linked to their global account permissions.
So this means that if distributors that are signed up in beta 10.1 can emulate their customers, they will always see their distributors 10.1 beta info on their customers auth & provisioning and download portlets. At this point, distributors will not see their customers 10.1 beta authorizations. The filters can be used to remove the 10.1 beta authorizations from view. The filter is available at the bottom of the portlet for Auth & Prov portlet and at the top right for the Download portlet.
Summary - Don't expect to be able to "override" a Customer # and be able to see the licenses associated with that customer number because you won't be able to. Beta licenses are tied to Global Account, period.
[edit] How can I at least see what a Beta Customer would see in Customer Care Portal?
Customer Care Portal Login for beta-like experience:
URL: https://customers.esri.com LOGIN: ssluser/ssluser