Why does my SD card need authentication to access?

I'm running Ubuntu 14.04 on a Toshiba Chromebook 2 via crouton.

I recently reformatted a 256GB SD card that I keep in my chromebook at all times. My problem is that every time I try to access my SD card after waking up my Chromebook I am greeted with the message

Authentication is required to mount SD256 (/dev/mmcblk1p1)
An application is attempting to perform an action that requires privileges.
Authentication is required to perform this action.

Action: org.freedesktop.udisks2.filesystem-mount
Vendor: The udisks Project

I'm curious why I have to authenticate my SD card each time I wake up my chromebook and whether or not there is a way to change this.