I just had a similar issue with my 2012 model pn64E8000 that I bought from Best Buy. The Geek Squad came to my house twice to look at the TV and concluded (based on the shape of the crack) that someone must have thrown something at the TV despite no exterior markings on the plastic sheet covering the glass and the fact that it happened while everyone in the house was sleeping. It was under warranty, but I can't get it fixed by them under the warranty coverage because it does not cover damage due to impact.
The spider crack has a small circle in the middle of it. I'd be interested in anyone else who has had similar experience.
We've had this tv less than a year. Tip top condition, looks brand new - because it basically is! Tv all of a turned on with a black screen and weird noises. Samsung sent a tech, tech said it's an internal crack caused in manufacturing. Said it can happen in plasma's and this models had trouble with it. Called after a week of not hearing about parts, and now samsung says it's external! They told me no ones spoken to the tech who actually looked at the tv, and they can't tell me how this is determined, just that "they know"! Sounds like I'm one of many dealing with this warranty scam. I know I'll be cc'ing the attorney general on a written letter to samsung regarding this dispute. And be yet another filing a complaint with the BBB. I suggest everyone else do the same.