Why are GNOME RPMs non-relocatable?

[Tim Moore <tmoore tembel org>]

There's a comment at the beginning of all of the RPM spec files saying
that the packages aren't relocatable. Why is this? They all use prefix,
the prefix is passed to configure, and I know that people have been able
to relocate tarball installations by using the prefix flag on configure.
So what makes the RPMs nonrelocatable? Or is that comment in error?

Tim