[Bongle]

Another hit against "rift as safety glasses" is that although it has the plastic case, what is actually near your eyeballs is lots of glass in the form of the screen and the lenses. If it gets hit hard by a projectile, it might break the screen or lenses and send the fragments into your face.

Then there's the issue of, even with an on-rift camera, not really being fully aware of your surroundings. If a tote somehow gets chucked over the player station you might not notice and might not get your arms up to protect. Or if a robot rams the player station, the disorientation might make you fall over (search youtube for oculus pranks where people nudge oculus-wearers: it's not easy to stay upright when your vision thinks you're somewhere else).