Answer 1

You can use WSS without a TFS CAL as long as you don't touch data that is stored in TFS (such as the documents).

You can use the reports without a TFS CAL when somebody with a CAL exports it to pdf and sends it *manually* by mail to you.

You can use WIOV without a TFS CAL to create  new work items  and see the work  items you have created  yourself

In all other cases you need a TFS CAL

Answer 2

Thanks!

I was afraid about such an answer.

But for the WIOV I have to give users the Contributor permission.

Who is responsible for the abuse, if the customers  use a different client?

I don't wanna end up, giving customers access to WIOV for entering WIs and then ending up with a claim from Microsoft because they use Team Explorer to access data.

What about EMail alerts? Are they allowed for no CAL users?

Would be an easy way because there's no need for adding an account for the customer.

Answer 3

to avoid a user  to access data, you just have the deny the permission  "use full  web access features". see this post for more information see: http://blogs.msdn.com/b/serkani/archive/2009/12/31/how-to-enable-work-item-only-view-in-team-web-access-2010.aspx

About the email alerts i think that you can apply the same rule that Edwald said. If you send the email alert to a person who have the cal  license, this person ca manually forward the email to another person. 

The general rule is that you cannot use a software or a hardware to automatically extract data from whithin the tfs, but you can distribute static data manually. I think that you can do this as a pdf, a printed documment, os a email, but you cannot do this via a excel file that access the data directly from the tfs, because this wont be static data.