bitcoin-qt tries to randomize the position of the change output, but I believe the code has a flaw:

// Insert change txn at random position:
vector::iterator position = wtxNew.vout.begin()+GetRandInt(wtxNew.vout.size());
wtxNew.vout.insert(position, CTxOut(nChange, scriptChange));

The problem is that size() is one in the common case of one payee, so GetRandInt will always return 0.The change ends up in the first output.

I think it should be size()+1.