A while ago, I saw an ad for a small sport boat with the tagline: "The speed, up to 60 mph*, is simply incredible!"

Then, later, in the fine print: "*Achieved with a professional driver on a closed course using a specially tuned engine and custom propeller. Do not attempt."

Advertised speed capabilities are useful in understanding how a boat might behave, but they don't mean what you probably think they mean- even if the vendor isn't fudging them.