Well, it's a bit of a quandry, isn't it? I mean, I assume my feelings, wishes and desires must count for something, too. Surely it isn't all about making the cashier happy. That's definitely more interaction and responsibility than I wanted from just running an errand to pick up a few necessary items. Maybe the cashier has some responsibility to report to management that being forced to make the same speech to every customer, even ones she knows will decline every offer because they have repeatedly, and look uncomfortable, is not such a good sales strategy. It's possible that could have some effect.
Are you really insisting on enthusiastic participation in "Would you like to apply for our credit card? Buy this hand lotion? Get this chapstick? Did you see our blah de blahs? What's your phone number? Your address? Your zip code?"