iCloud holiday calendar appeared in Calendar app I opened up Calendar this morning and a new calendar appeared under "Other"

The calendar is Mexican Holidays and it is a calendar subscription from iCloud. I didn't add it nor do I live in Mexico. I have seen this on a few Macs in our office all running 10.9.x

Calendars include Mexican Holidays, Canadian Holidays and Hong Kong Holidays.

Is anyone else seeing this behaviour?
Managed to confirm this with a few admins in NZ/Aus. The Show Holiday Calendar is on and for users in NZ there doesn't seem to be a NZ Holiday calendar so we are getting results such as Hong Kong, Canada and Mexico...

Users in Australia are seeing the correct Australia Holidays calendar.

However we aren't exactly sure what triggered the calendars to show in the first place...