It depends on how big the silver market is compared to 800 million ounces. If someone with no short exposure and lots of money starts buying it, and BofA has to cover their shorts, then something like Gamestop will happen and a major bank will blow up.
The silver market has been cornered before, in the 1980s, quite famously, in an event that moved the price by a factor of ten (order-of-magnitude).
https://en.wikipedia.org/wiki/Silver_Thursday
