First time Cadillac owner. Traded in a 2013 Corvette Grand Sport, and have no regrets. The 2016 ATS-V is amazing except for one thing. Whenever we go to Ceasars Windsor underground parking and stay in hotel car battery is dead a few days later. We have nothing plugged into car and Valet was u we careful ensuring car off and locked second time. We have left car idle outside for 5-6 weeks and many times for days and days before with no battery issues. No other problems between hotel visits. Thinking it might be On-star trying to get a signal but dealer says On-star will not kill battery as it is disabled if voltage drops. Anybody else experience this or have any ideas?