fail last night on QF549
We approached the line half way through boarding, a couple in the general line saw that they could get through faster in priority so they ducked under the rope to join the short line just ahead of us. Then from behind us "excuse me, I'm with them, we are several"as one of their friends shoves past us - I respond with "well, so are we" which was met with a sheepish grin, then another "I have to be with them, I've got the boarding passes", eventually this group turned into six people. It wasn't possible to physically block any of them as they passed so we just had to suck it up.
Much confusion and farting around with boarding passes as they reached the agent, who greeted them merrily with a sort of "no problems, take your time" look and much happy banter, and I last observed them merrily barging their way down the aisle towards the back of the plane.
(others from the general line took the hint from this lot and started ducking into the PB line following us)