A dual carriage way I regularly use has a section down to one lane for roadworks for about 9 weeks.
There are signs telling you how far until the merge and there is even a sign 800yards before the merge that says 'USE BOTH LANES' yet still people insist on sitting and queuing in the lane that's staying open. The queue then stretches back into the normal dual carriageway. One lane standstill, one lane empty.
Drivers then try and stop me from merging at the merging point because I've not been sitting in a queue like a mug, and have used the open lane (as directed!)
YANBU: Both lanes are open until the merging point. Use them.
YABU: Start queuing straight away like a good British Citizen.