well if its in the kiosk...
you can stand up and play!
I have a used normal Dreamcast that has no skipping; no dead controller port. Doesn't mean it's any more durable.
My point is, I wouldn't want to treat a kiosk unit any less carefully than a normal Dreamcast because there is no guarantee it's any stronger. If you're talking more along the lines that a kiosk unit could last longer, it really depends on how much you use it and what conditions it is exposed to. Even movement can cause something to mess up at any point in time with any of the disc based systems.
I thin k the pre-release rental units also had empty plastic shells in place of the modem.