As far as luggage priority ‘issues’ are concerned:
My understanding is that the barcode on the luggage has the information on class of service / status and that this then determines how it gets loaded / delivered. The tag itself has little influence on this, it is more to please the customer.
Having said that, Mrs t who is a Gold member and therefore has priority luggage benefits, once travelled in Y on a ticket paid with business rewards points. She checked in at the J desk as usual and the BP did not show ‘gold’ like it usually does (this appears to be an issue with this type of ticket but that’s a different story). She however convinced the check in agent of her status and a J tag was attached to her bag. On arrival, the luggage came out with the general Y bags and the tag had been ripped off. That sort of confirms that the tag by itself is no indicator. But there appears to be someone removing priority tags from luggage going into the non-priority luggage containers.