Originally Posted by Sneezy

No, don't use an incorrect CC number. Fill out the page - leaving all CC data totally blank - then turn OFF Javascript by going through however your browser does that. Then hit the purchase button. The CC number is validated for correct form on your box by Javascript. Turn Javascript off and you can send any data you want to UA.

Without a CC number your itinerary can't be ticketed and will go away in 24 hours, but it will be booked, and without the possibility of selecting someone else's CC number.