Of the 110 or so cats we have adopted out, we have arranged for perhaps 4 declawings to be done at the time of sterilization. We do not support it in any way, and will recommend nail clipping or scratch boards as an alternative. However, in the cases where we have arranged it to be done at the time of sterilization, we determined that the kitten was (a) definitely going to a super home, (b) that the sterilization/declawing was done through a specific vet who has an excellent pain management procedure (keeps the cat at the clinic for 3 days after surgery), and (c) the adoptor pays the vet directly and at full price for the declawing.
I know that some adoptors may not admit to their intentions of having it done and will subject the cat to 2 separate operations if we don't allow the cat to be declawed at the time of sterilization. They may also look for a 'cheap' deal whereby the procedure is not done properly and the cat suffers needlessly.
We will not allow declawing of any adult cat, under any circumstances (adults are always sterilized prior to being put up for adoption, so there is never an issue).
I hope we can put this subject to rest.