A commercial client calls to say they found the same coverage for a lot less, often through an instant online quote. For many trades, a big price gap is the first sign the business was quoted as something it isn't.
The classic example is a kitchen exhaust hood cleaner quoted as a janitorial service. The policy looks similar on the first page, but the class code describes a different, lower-risk business, and that difference tends to show up at claim time or at audit.
Why this happens so often
Many standard admitted carriers, and most instant online quoting programs, don't write higher-hazard trades like hood cleaning. Those businesses usually need a surplus lines quote. When the exact operation isn't on an online program's list, the buyer picks the closest-sounding class, and "janitorial" or "cleaning services" is a common landing spot.