I used to do the 'proper' thing.
It happens so much round here... on the 4 lane stretch of the M1 people round here seem to think it's ok to just sit in lane #3 (with lane #1 being the 'slow' or only lane that isn't an overtaking lane).
Usually at about 60mph.
I can't be bothered with them any more.
If I was to get stopped and questioned about it... my explanation would be that it's a lot safer to stay in the normal lane and continue on as expected as long as there is no obstruction and attention is paid to the numpty in lane #3... rather than switching 3 lanes to the right and then 3 lanes back to the left.
Even if it's just a 3 lane stretch... same applies.
2 lane could be a bit more awkward to explain to certain traffic cops... however if the person wasn't sitting in lane #2 for no reason, I would not have had the ability to pass them on the left. If I have the ability to pass them on the left, then they are in the wrong lane and performing an incorrect manouver... they are the ones who should have been pulled over, not me... while 2 wrongs don't make a right, I would not have had the ability if the other person wasn't a twit.
I used to get annoyed with them, now I just ignore them... heh... sometimes I would **** with them... would almost certainly have a faster car and would play with them til they decided to choose the correct lane or I couldn't be bothered driving so slowly... I can be a ***** at times
