ICAO Doc 4444 para 7.4.1.2.2 states that before takeoff an aircraft shall be provided any significant changes to the wind that was provided prior to taxi (ie, on the ATIS). I'm trying to locate what 'significant' means, but I am sure I have read 5 knots and 10 degrees somewhere. Will keep hunting.....
Oh, and if the ATIS is changed while an aircraft is taxiing, the above provisions must be used, as an ATIS change is made because the comditions have changed. The tower or ground controller will most definitely pass the new info on to pilots - it is essential to their operations.
However, passing the wind on departure for the sake of it is not essential - why not pass the temp and QNH too then? I know, because they haven't changed and if they have, they will be passed. The wind is no different.
Cheers,
NFR.