UserEvent connected to applications folder on an attached partition

This doesn't happen on a bare-bones Mountain Lion installation. My regular installation goes back to 2007, has had numerous software updates and has a fair amount of third party software.

When I mount the partitions on my Drobo S, I typically get the following type of connection [output from lsof].

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME

notifyd 14 root 297r DIR 1,12 1360 2 /Volumes/B6

notifyd 14 root 298r DIR 1,12 442 421104 /Volumes/B6/usr

notifyd 14 root 301r DIR 1,12 238 130854 /Volumes/B6/private

notifyd 14 root 304r DIR 1,12 136 137088 /Volumes/B6/System

notifyd 14 root 307r REG 1,12 8192160 3538524 /Volumes/B6/mach_kernel

notifyd 14 root 315r DIR 1,12 2448 280507 /Volumes/B6/Library

mds 39 root 64r DIR 1,12 1360 2 /Volumes/B6

UserEvent 915 rbp 137r DIR 1,12 2040 463868 /Volumes/B6/Applications

UserEvent 915 rbp 138r DIR 1,12 1360 2 /Volumes/B6

The two UserEvent entries prevent me from dismounting (ejecting) the partition. They do not exist on partitions I can dismount.

I am at a total loss as to what is creating this. Consequently, I can't begin to determine how to prevent it. PID 915 referes t the UserEventAgent, which I presume sets this up.