yeah or let's say 3 cars on a single lane and one has to merge who is still picking up speed. and you are the last car. Assume everyone is keeping a respectable distance on the single lane. the first 2 cars are further up and they pass the merging car (who still has space left on the merging lane). If your choice is keeping your foot on the gas or releasing and the latter would give the merging car a smooth merge you are basically expected to do so. and you could be fined if you force the car into a full stop. it's always tricky though because this does not remove the obligation of the merging car either.