I've heard this from some reputable source..
oh, now I remember. It was on CarTalk, and some guy said in the owner's manual for his VW it said to avoid keeping the wheel at full lock for longer than 10 seconds. And Tom and Ray confirmed that there was more stress on the system at full lock, and over the long term it could increase the odds of a problem occuring.
So, no, I don't think you are being paranoid. But if you need to use full lock to make a manuever, you should do it.
I don't worry about these things much, my power steering system already leaks! ;-)
--Peter