The listing standard requires that the smallest digital clock or night light you can plug in a 5-15 or even a 5-20 will survive a fault on that circuit whether it is 15 or 20 amps.
The cord is required to be 18ga or sized to the load.
There are all sorts of protections built into the code and the listing that make that "less than 16a" load safe.
As for "damage" vs "severe damage", it is really what the inspector thinks is "severe". (EMT vs RMC)
The code does not try to make that call but we have the tool.
