Especially given that an adequate alternative to putting all your money in one bank is to put it into two banks. Unless you're already on thin ice, that solves the short-term cash flow problem. Historically, even in bank failures, depositors get most or all of their money back, it just takes a while.

And if that isn't adequate for a given company, it sounds like it's time for them to hire a finance professional who has experience with cash management.