I don't like that feature either. I don't need to have everyone I have ever sent an email to, to suddenly getting request.
I get a lot of phishing emails from non-LI people requesting a connection. I always make sure that I am actually logged in to LI and review the requests from there.
It's a handy tool, as long as people don't try to make it into Facebook, although I call LI, "skynet". :-)
I’ve had a few friends get laid off from where I work, and I found it a great way to keep in touch with them. I have just a handful of contacts there. I have the “free” account so I can’t do much on LI.
(I should look you up.)