Redistributable SQL Express Registration Requirement?

I noticed that Microsoft gives license to redistribute SQL Server Express as part of an application (though we have to register for this - http://www.microsoft.com/sql/editions/express/howtobuy.mspx).

So we would like to take advantage of this, and redistribute SQL Server Express 2005 as part of our WinForms application (using the method described http://blogs.msdn.com/sqlexpress/archive/2006/09/20/763956.aspx or http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnsse/html/emsqlexcustapp.asp)

My Question is: If we perform a silent install on the client machine (included with the installation of our application), are our end-users required to register Sql Server Express in order to use it? From this page (http://msdn.microsoft.com/vstudio/express/register/) it appears that in order to use an Express version for longer than 30 days, one is required to register it. However, requiring our clients to register their version of Express kind of defeats the purpose of our using Express as our database format. We need a database that we can distribute with our application, that the end-users can use without having to register.

So is the redistribution license enough (in order that the end-users do not have to register their individual copies)? Or will the end-users also have to register their copies (in which case we probably cannot use SQL Express)?