Comment # 13 on bug 908383 from Wolfgang Bauer

(In reply to Fabian Vogt from comment #12)
> Adding needinfo to virtualbox maintainer.

I'm not a virtualbox maintainer, but according to the changelogs this
requirement was added to openSUSE's packages because /usr/ might be on a remote
file system.

Thu Aug 26 11:17:33 UTC 2010 - gber@opensuse.org

- made the vboxadd init script depend on $remote_fs since it
  requires /usr to be mounted

(this dependency is also added in the vboxadd init script that starts the guest
additions, the change to vboxdrv is not mentioned in the changelog but has
likely the same reason I suppose)

Personally, I don't think it should be the job of the vboxdrv service to take
care that /usr/ is mounted already when on a remote filesystem, so I'd say this
could be removed. 

Btw, this dependency is also added in the vboxadd init script that starts the
guest additions.
And the dependencies are actually added by openSUSE-specific patches in the
package (vbox-vboxdrv-init-script.diff, vbox-vboxadd-init-script.diff), so I
think it would be better to change those patches than add another one on top.