Have a friend take a video of your phone messing up in case it decides to behave while your at the Apple Store. That way you have the proof of its odd behavior.
I find it difficult to get someone to shadow me 24/7 just to video my iPhone. The only one to volunteer wants $20/hour plus meals. A couple of days of that & I might as well have bought a new iPhone.
On the bright side I haven't had any hiccups lately.
Had a new one yesterday.
Phone was in my front pocket as I hiked for about an hour. Didn't use the phone.
When I took it out of my pocket it was open & unlocked and there were about 10 different apps open.
I don't even see how it unlocked itself much less how those apps opened.
I updated to 9.2 about a week and a half after it came out and I am a happier puppy than I was.
I haven't seen any instability at all.
I never found the time to have my phone checked out by Apple & I'm glad I didn't have to resort to a major reset!
Thanks for all the input, folks!
I'll post again if some gremlin pops up, but I'm optimistic that the update healed my ills.