In SQL Server 2008, when would I use a full text index that covered several tables?

I wanted to do a full text search across开发者_如何转开发 several related tables in SQL Server 2008. From browsing this site I've realised the best option is via a view, but initially I thought I was meant to add several tables to the same full text index via Management Studio. I started to do this and realised the index would have no idea how they were related, so my question is: when would I want to have a full text index covering several tables in this way?

Apologies for the vagueness, I am just trying to satisfy my curiosity after Google let me down.

Create a view on multiple tables and then implement full text search on that view