So, here's my experience with this. I bought my first nexus 7.2, at a best buy in north Dallas, in October. I experienced random reboots, right out of the box, about once a day, usually when I was browsing chrome, or when the tablet was sitting on the home screen without being touched. My gf bought a nexus 7.2 as well, at the same store in November, and she was not experiencing any random reboots, hers has always been stock, to this day (my suspicions began). I figured it was a software, or app problem, and waited for a fix from Google, or my app developers. Tried various custom Roms in the meantime (cm11, dirty unicorns, silmrom, and many more). I also tried various kernel's, in combination with said Roms (Franco, ElementalX, glitch, bulletproof). I had random reboots with all combinations of Roms and kernels. Did a factory data reset after every update from Google, and tried it for a week or so every time. Still experienced random reboots. I finally got fed up and took my table back in early January, to the same best buy in north Dallas. After receiving my second tablet, I kept it stock for a week, and then restored my preferred twrp backup, that I had taken with the rebooting tablet ( stock 4.4 krt16s, xposed framework, ElementalX 2.2 @1.7 and 450, with the motoX dalvik and bionic patches). With the new tablet, I have not experienced one random reboot, either with the stock software, or the custom software.
So, long story short, if your experiencing random reboots, if you have the ability to, I would take it back. Maybe you can fix it with software enhancements, but IMO it just shouldn't do this, stock or otherwise, and warrants a return.
Whatever you choose to do, I hope it works out for you, the reboots were personally driving me crazy, and I'm glad my second tablet doesn't reboot like its got a mind of its own.