Howdy danfeeley,
That’s a good question, the topic is a couple of years old by now. I looked into it and all of Barry’s advice seemed quite relevant still. Changing the submission URL to something you can detect should be easy enough with a theme override (Themer’s Guide). You could concatenate “&add-to-cart=1” to the end of it, then take action on the cart page redirect anything with that request to the checkout page. The editable URL can be found here:
/wootickets/src/views/wootickets/tickets.php
You might even be able to just change the submission URL straight to checkout page instead of the cart. I am not sure if that will work, but it could be worth a shot.
Does that all make sense? Will that work for you? Please let us know.
Cheers!
– Brook