sbiddle: Kathmandu used to be the worst offender when they started source tagging all their goods and not bothering to deactivate tags correctly st stores, and for a long period of time weren't doing any deactivation of goods from their mail order (something I blogged about here). This type of attitude ruins the whole integrity of the EAS system making it pretty much worthless for any retailer trying to use it.
I think there was a separate problem for Kathmandu - they used to sew some kind of "echo location" tag into their clothing labels that was intended to be used by mountain rescue crews to detect people who had been buried by avalanches, and these tags were setting off retail security systems. I know I set off the alarm going in to The Warehouse in Queensgate, Lower Hutt while wearing a Kathmandu jacket that I had owned (and had removed all store tags from) for about six months. On this occasion I was asked by someone at the door if they could look in my bag and I was happy to comply - I didn't have anything to hide. The alarm went off again as I left and the same staff member just smiled and waved me through. Although I consider myself an honest person I couldn't help thinking what a great opportunity that would have been to nick something!