Personally I'd say no. Say that my BTC wallet once contained 100BTC but I spent a lot of it up until the fork and thus only had 15BTC left when the fork happened, I can't really expect to demand the BCC associated with all the 85BTC (I spent) from the sellers. I think the same applies to deals made here or elsewhere.
There would be no BCC associated with the 85
BTC if you spent before the fork.....
You should have 15 BCC to match the 15
BTC that was in your wallet on the 1st of August
Exactly. The point is that these coins were also 'spent' so to speak and therefore the buyer shouldn't have any claim to the BCC tied to them.
Just to play this out fully, what of the counter-argument that the original deal was only for BTC and BCC did not exist when the deal was made. Additionally, there are some minor hoops to jump through to retrieve the BCC. Is the buyer (person paying in BTC) obligated to retrieve the BCC for the seller (person receiving BTC as payment)?
Well if the BCC didn't exist at the time of the transaction then what is the claim? The coins should be looked at as spent BTC and therefore all associated BCC would also be spent. At the time that the transaction was agreed upon there was no BCC to claim so you can't really retroactively claim it back.
Since redeeming the BCC can only be done by the buyer or Escrow holder I think that since they have to go through some trouble they should definitely be compensated for it.