I see that easily a problem in a sealed enclosure, probably just as much a problem in a shared port as long as the remaining driver is above the cabinet resonant frequency. From what I have read, I think the port may be a safety relief valve if the driver is being driven below cabinet resonance. Being new to the study of cabinet acoustics, I found after all these years that the port does not drive air in/out until the driver is below cabinet resonance, and actually the port is as if it were blocked when operating within it's design frequency. I'll need to find time to understand why then it's more efficient than a sealed cabinet.
When you get air blowing in/out, you are below cabinet resonance. That should put less pressure on the other driver at the long wavelengths that would push the weaker cone farther and maybe into failure.
Ok, it's getting late, I'm not writing well so I'll try again when I am better up to it, if this is not easy to understand.
I guess it's not much of a worry, but individual cell ports are put on high end cabinets as part of that model hierarchy in which higher end models usually include across the board upgrades, not only gold plated wires and better driver.
