If you'd said in advance that I had to do that before replying, then sure you'd have a point. You can't apply the condition after, I can't give you a DVD for fr

If you'd said in advance that I had to do that before replying, then sure you'd have a point. You can't apply the condition after, I can't give you a DVD for free and then demand payment after you've watched it if there wasn't a prior agreement.