Help! Offline files are going nuts

Ok, I ran into a VERY strange problem today. Last night i setup one of
our mobile users for offline files( he is the first in our company to
ever use it) so i went to our shared drive for the home folders(
\\server\home$, that everyone has a folder in. mapped to U: on their
work stations, and that My Documents is redirected to) so, anyway i
gave domain users read permissions on that folder, and got the laptop
setup for offline folders, synced and called it a night. This morning
when i get in i get calls from almost everyone in our company saying
that their U: drive has a funny little icon on it. So i go and look and
now everyone in our company has their home directories showing that
they are offline files, when people log on and off windows syncs the
files and everything. So my question is, how on earth did this happen?
I didnt change GPO because we never set any of the options as far as
offline files. So i have no idea how it got started or how to fix it.
Any insight would be very helpful. Thanks