A passed through disk will not autmount. If it's passed through and mounted by a docker container or VM and UD mounts it, there would be data corruption.
Probably the best way to handle this is with an enable check box like that used in the recycle bin plugin, and on the plugins page.
The 'Unmount' button would not be enabled until the check box is checked. It would be a bit harder to acidentally click the 'Mount' button.
I'll have to think about this a bit though to be sure it makes sense for everyone.