The re-opening of the the River Mountain Road access to the Two Rivers Bridge parking lot was followed quickly by multiple car break-ins in the lot. Smash-and-grabs have been an ongoing problem, mostly on the Little Rock side of the trail, and they often occur when you would least expect it; in broad daylight with crowds around. In one case a year or two ago, the guys had a bike on a rack on their vehicle and would fiddle with it until the coast was clear, then smash the window of the cars close by, take what they could grab, then drive away.
The most recent thefts, witnessed and caught on video, were by guys wearing hard hats so that they fit in with the recent presence of construction workers in the area. Do not leave anything valuable in plain sight! It is no guarantee, but may at least cause the thieves to move on the the next victim.