When I discovered the tag on my trousers that I purchased from Dunnes, I thought no problem, I will go to my local branch and they can remove it. They didn't even do tags in that branch so didn't have the machine. They sent me to a local sports shop in case they could do it for me but their tagging system was different so they couldn't help me, and I didn't have time to return to the original store.
Yes, this was an inredible oversight. Aside from your issue, it also affects refunds- items are taken back to a different store, then that store has to send them to a store that can take the different tag off and sell it there. The black circular tags with dye in them are used by less important stores- your average Dunnes. Massive Dunnes and flagship Dunnes use the newer ones, the white thin ones. Cornelscourt, Blanch, Liffey Valley, Stephen's Green, Henry Street all do..so stores along those lines. So it doesn't have to be removed by the original store per se. Black tags are removed by a strong magnet attached to the underside of the till, or loose. White tags are complicated to re move, and the system is built into the counter. So white-tag stores can remove black tags as they usually would have the magnet thing lying around, but vice versa does not work.
The white tags were introduced as they're impossible to remove by hand, whereas the black ones an be done.
All tags are aimed to be at a seam so the pinprick left is not noticeable. They are quite diffiult to aim though in some garments. There is no other way though of applying a tag to clothes.
'Fake' tags do not exist, in Dunnes anyway. The black tags and white tags are not deactivated at the till, they are seperated and reused constantly for new clothes coming in. Once joined, they work and set off alarms. The problem which they may not have wanted to draw your attention to- is that plenty of Dunnes do not actually have security barriers. So they serve mainly as deterrents. The sticker tag with the barcode that you see on CD's and makeup is the only one that could be 'fake' as it isn't taken off, just deactivated.
Some stores have a sensor built into the counter so if you miss a tag, when you're placing the customer's bag on the counter it beeps! Stores should really think about that one. Particularly if the store has no actual barriers.
Out of thousands of transactions, people are going to miss a tag eventually, particularly if exhausted, or run off their feet. Cashiers are only human and what's quite common is having two tags on the one thing by accident so when one is taken off, nobody goes looking for more. Just like it's easy to miss asking 1 out of hundreds of people for their clubcard. However, staff initially should be trained better, I totally agree. Some have only a vague idea when new about taking sales at all, never mind tags. Also no excuse for not taking a tag off when presented with the receipt- that is the height of bad customer service.