The first two times I deleted my account, my account magically resurrected itself after I accidentally clicked a link to a LinkedIn page and my password manager automatically logged me in. Apparently logging in resurrects deleted accounts, no questions asked. After the second time, I wisened up and removed all my LinkedIn cookies and disabled my password manager for the domain, then deleted my account for the third time.
That had worked for a long time, until just a few days ago, when I received a random LinkedIn newsletter out of the blue. This was disturbing. I clicked the Unsubscribe link, which asked me to log in, but my login didn't work (which is nice, because apparently my account is slightly more deleted now). So I tweeted at LinkedIn, and they said they put my email address on their Do Not Contact list.
Hopefully the reign of terror is over, but I somehow doubt it.