No. You are right about panic buying. But LA happens to be one of the epicenter of supplies from the Pacific. If you drive between the Port of LA in Long Beach, and DTLA you hit multiple warehouses full of just about everything, then distribution fans outwards.
I haven't seen a lot of ass-wipe hoarding around here.
If there is something that could start a riot, it might be people being shut in with their dysfunctional relatives.
Actually I would be afraid of riots beginning in oversaturated medical facilities. Imagine how you would feel, after a 6 hour wait in the ER with your sick spouse, when you are turned away because they have no more room or resources to treat him. And there are like 10 people ahead of you waiting and another 10 behind ...