A route bus did this to me yesterday. There was good advance warning that the left lane was closed for work, and all the cars merged to the right lane and took up their place in the queue. Of course, the route bus went right up to the merge point and then use its little merge sign to force its way ahead. All up it saved the bus around 5 seconds, but ticked off a lot of drivers.

The thing about merging is that if there is no distinction between the lanes as to which continues and which ends (i.e. just a sign that says "Form one lane"), you have to perform the "zipper" merge and are obliged to let the "offending" cars in.