Dead Battery

[H3PAC]

Well, almost dead. My new vehicle, with only 1,200 miles on it, has had progressively weak starts for the past 2 days. No problems prior. Barely turned over when leaving for work last night. Parked at work for about 9 hours and needed to call Hummer Roadside Assistance to have Sparky (I swear the guy's name was Sparky - you think I could even make that up?) come out with a battery pack and jump start it. Ran fine, charged right up from the alternator and no idiot lights or messages. Did not leave anything on....only factory/dealer installed electronics....it's a mystery. Any known issues that could cause a continuous power draw that resolves itself? Or, can a bad battery behave so strangely? Since I didn't see any idiot lights, and the battery seems fine now, is there any value in bringing it into the dealer to be checked? Or should I wait and monitor things for awhile? Should I stop using so many question marks???