I have had it happen on 2 different LG 10.2 Tablets. The first one was only 2 weeks old. It was on the charger overnight and the cracks were there in the morning. Two weeks later, the other unit was cracked. It also was on the charger but for only a few hours.
We are getting no satisfaction from either LG or Verizon. LG had us send both units back because we believe they are defective. Now they say they do not cover screen cracks. We told Verizon and they said we could cancel but there is a $750 cancelation fee. So we continue to pay for no service for 2 more years.

I will never buy another LG product.