for example:

$ TZ=IDIOT date
Wed Jan 19 19:54:58 IDIOT 2000

here it's harmless. but for 
$ TZ=PST date
Mon Feb 12 09:34:02 PST 2007

it's not ast the correct value is:
$ TZ=PST8DST date
Mon Feb 12 01:34:14 PST 2007


Attached is a patch that do not reuse TZ value if no offset was provided, and 
that instead clearly state that UTC was the chosen timezone to display the 
date.