Side effects of CLOSE_ON_EXIT

I was wondering if there were any side effects of setting the configuration variable CLOSE_ON_EXIT to a 1.  We have come upon some situations where developers have forgotten to close files opened in their programs.  I cannot find what issues could arise using this option only a place in the docs that indicate that it is not ANSI compliant and, therefore, not the default when using runcbl.

I think that another option that I would prefer is to inquire of some way to log when a program exits with files that are open still so that the programs can be fixed.  Is that possible?