Some of the arguments here are just getting silly.
What does it matter if the dog has no genetic links to the cross the person asked for if they are basing it on LOOKS! If they don't care about breeds why would they care what breeds go into the CROSS!
It's funny how the advocates for cross breeding are (and this is not meant in an offensive way) the average pet owner. While the advocates for purebreds are those who have spent years (decades even) breeding themselves and learning about dog genetics.
I have yet to meet someone with extensive knowledge in dog breeding condoning cross breeding.