If the fermenter is not specifically designed to hold pressure, your high-pressure demo would leave the opposite impression on me then you intended. In fact, it would scare the hell out of me because my assumption would be that it would not be designed for holding a significant amount of pressure. I have spent many, many years in laboratories with both large surface area pressure vessels and vacuum vessels.
On the other hand, if they are rated to hold, say, 100 psi, and you are demoing them at 80 psi, my question would then be: why I would ever want my fermenter to be at 80 psi? I would be much more impressed with clear demonstrations of the features I would care about: easy access, easy to clean, easy temperature control, etc.