Sometimes there are things that occur only when the moon is full.  Let me 
give you an example.  The government changes the date when daylight 
savings time occurs.  Without being current on PTFs you will get burned. 
(Unless you're in Arizona.)
Let's say that it uses Java or some such thing under the covers to send 
hardware alerts or whatnot.  And it does some sort of SSL communication. A 
PTF could bring down a new certificate to replace one that is about to 
expire.
Search the following for 'integrity'
http://www-912.ibm.com/a_dir/as4ptf.nsf/$$search?openform
IBM fixes a lot of holes.  Holes bad enough that they won't put what they 
were in the ptf cover letter.
These are things which could affect you even if you're running in a fat, 
dumb, and happy environment doing the same application you've been running 
for the last 15 years.
Can PTF application cause issues?  You betcha.  There's just something 
invigorating about having to run ENDJOBABN several times a day because a 
currently supported version of Sametime, on a currently supported version 
of the OS, and both are supported for each other, stops working because 
the Java group ptf (several levels down) is too new.  (current open 
pmr...)
Rob Berendt
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