I learned why it is very bad practice to include multiple files in a msi component. A msi component should contain only 1 file. Good references can be found here :
http://blogs.msdn.com/b/windows_installer_team/archive/2006/05/01/587990.aspx
http://geekswithblogs.net/akraus1/archive/2011/06/17/145898.aspx
Wix: one file per component or several files per component?
My question is: since this one file per component rule is so important, why does the wix compiler accepts multiple file per component ?