I don't think any of this is considered panic buying or panicking. This is more like preparedness.
You'll know if we hit panic when people trample on each other, fight for food, begin to loot etc.
For instance, there's a few videos of people lining up with carts to get into the Richmond Costco. Or this video from Hawaii titled "Panic Buying at Costco", but really it seems extremely orderly lol.