I had a goodie a while back in my Hiace campervan (read: 1987 Hiace with big bull bars and such a faded paint job that looked like it'd been sand blasted.)
Was in the T2 lane, because there was two of us in the vehicle, and when merging with the rest of the on-ramp this guy in a very new and shiny Toyota Prado 4wd thingy was well behind me, but sped up and tried to merge into me. Not infront of me, but stayed right next to me.
He started yelling about it being a bus and truck lane - I yelled back 'yeah, and see the T2 on that sign, and there's two of us in the vehicle'. He actually hit my wing mirror with his car, so I yelled "my van's real cheap to repair - let's see who comes out worse off" and held my ground. His mirror scraped all the way down the side of my fan as he finally backed off. Leaving a dust free line down my fan, no scratches on it though, whilst his wing mirror had a chunk taken out as it slid past and clipped the back.
I hung my head out the window and laughed at him and all the other motorists around him were yelling and tooting at him and yelling to me "good on you. That guy was an idiot"
Made my morning that's for sure
But yeah - it's not LAW to merge like a zip. It just makes things easier.
I always thought that when it comes to merging, it's not who's in the left or right lane, but who's in front, that has the right of way?