sbiddle:
VDSL2 is a totally different beast to ADSL2+ however, and there are good reasons to avoid "bad" connections as power levels and noise become critical for good performance.
Do you mean that if Chorus let too much people to connect to VDSL2 with attenuations such as 17db (using higher power levels) they will create more noise (and more crosstalks on the lines underground) and therefore may impact on the performance of the other people connected to the same, say, cabinet?