I have applied the relavant XFree86 patches and the utempter
patch to my Red Hat 6.0 installation. The utempter patch did
indeed fix the xterms that did not die after a user logs
out. However, when a user runs Mathematica 3.0 and exits the
mathematica kernel is not killed. It remains running and is
reparented to init ( pid 1 ).
Okay, turns out this is "normal" behavior for mathematica. This is NOT
a red hat problem.