Not sure what an open-plan office is. I did not use that term.
It's my desk and my Ethernet cable and it's plugged into my laptop. No one else sits at my desk and no one should unplug my Ethernet cable from my laptop when I step out of the office. Period.
Edit: So is an office with three desks (one desk assigned to each worker) an "open-plan" or a "shared working space"? Three people work in that office and they all have a key to the door.
If it's "your desk" where "no one else sits" then it would seem unlikely that you're in a co-working space. If you're in a place you call "the office" and other people have easy enough access to "your desk" to unplug your laptop, it probably has an open-plan.
If none of this is true, you might as well be talking about purple dogs stealing the umbrellas from your hamburger patch.
Most co-working spaces that I've looked into had options for fixed desks. Even if they don't, it might be nice to think you can go get lunch or a coffee without someone taking your desk (or ethernet cable)