VirtualBox notification at boot in Ubuntu Wily 15.10

[cogset]

In Ubuntu Wily 15.10, the following notification message is displayed at *every system boot* once the desktop graphical environment (MATE) is started:

 "VBoxClient: the VirtualBox kernel service is not running. Exiting."

To be precise, this is actually the exact same issue I also had in Vivid.

Ubuntu 15.10

virtualbox 5.0.14-dfsg-0ubuntu1.15.10.1
virtualbox-dkms 5.0.14-dfsg-0ubuntu1.15.10.1
virtualbox-guest-additions-iso 5.0.14-1~ubuntu1.15.10.1
virtualbox-guest-utils 5.0.14-dfsg-0ubuntu1.15.10.1
virtualbox-guest-x11 5.0.14-dfsg-0ubuntu1.15.10.1
virtualbox-qt 5.0.14-dfsg-0ubuntu1.15.10.1

What should happen: there should be no notification from virtualbox if there's actually nothing to notify, and the virtualbox application isn't even running.

What happens instead: at every reboot a notification from virtualbox is displayed.