I'm updating this thread with a data point in case someone finds themselves in similar boat. Some of the comments here indeed got me nervous. The award reservation was made from my aunt's AAdvantage account. Our family routinely books flights for each other from whoever has miles available at time when travel is needed. I thought we were being flagged for this activity. For my upcoming travel, it was my aunt who "splurged" and used miles in her account. Problem was she was 8000 miles short of the flight I needed to take. So I transferred miles from my account to hers. This cost me $90, I think. So with my aunt's account "full", she was able to book an award flight for me.

Many weeks later, here comes the dunce that I am. I was going through my credit card statements and noticed an unfamiliar $90 charge to AA. And yes, I did the unthinkable- I contested with the credit card company. And that started a whole avalanche of events. The credit card company honored my dispute and reversed the charge. Well, AA understandably responded with cancelling my trip because my aunt's miles stash would have been 8000 miles short. Somehow, this also caused my aunt's AA account to be locked. It's been unlocked since then and miles returned.

All this was explained to my aunt by Corporate Security or Security Corporate or something like that. So now, my aunt has been made whole. But I don't think we will be traveling on award for a while as this got us spooked. I'll be booking my same flight in cash- but we're still a little paranoid now. We read that 63 page Flyertalk post about AA fraud a few days ago and had been asking ourselves if our miles-sharing proclivity was the cause. Turned out it wasn't, but boy- what an experience..