An acquaintance of mine did. I had moved to a different state. We kept in occasional email contact. And one day I noticed he had deleted his LinkedIn account. Found him in the obituaries, he had passed on a couple of months before. RIP.
Isn't it more likely that a relative simply requested LinkedIn to delete the account? A LinkedIn account doesn't seem relevant to keep online at all after the person has passed away. Facebook, on the other hand, leaves pages up but with most features disabled except for the wall and photos - something I'm unfortunately familiar with.