Wrong priority
There is no point staying up at night worrying about a problem you didn't cause and you can't do anything about
Make sure your platform is secured in a way that accepts that these vulnerabilities happen and protects the wider infrastructure and your other customers.
If customer A does something dumb and causes a problem to customer A then it's not your problem; if customer A does something dumb and that can impact customer B then I don't want to do business with you because your platform is full of holes