I just tell them I have to sleep on all big decisions, which isn't a "no" so they have no recourse. Except the one time where, after multiple levels of sales people whittling down the commitment to around $500, the head sales person came over and said something along the lines of, "you're just here for the tickets, aren't you". That's the only time I even broke my script and said, "yes, and I've been here for 90 minutes, so where do I pick them up".
