I can imagine that ULD unloaders at some stations, if they fail to unload F baggage first or subsequent J baggage in order (through either a mistake or sheer laziness), might pull priority tags off as it gives them an excuse as to why the baggage did not get put on carousel in order.

For some, pulling some tags off is easier than dealing with an irate pax or dealing with an upset 'lost and found' colleague who may bear the brunt of the irate pax.