I haven't heard of of AA baggage agents opening bags and throwing in liquids. But, if you dropped them at the curb and stiffed the guy on a tip, it wouldn't surprise me, especially in SF and JFK and St Louis. I learned that along time ago. The guy in St Louis was a total jerk after I told him not to throw my bag around, so I didn't tip him. As expected, my bag was sent to Paris as I was sent to Montreal (pre 9/11)