And to go on a date where you are already certain it isn’t going to be, is an extreme lack of tznius.
And Kavod Habriyos, as well as Genaivas Da’as.
Of course, the idea is not to completely close off the possibility of Tachlis, but if it is (for example, you feel she is really ugly, or any other Chisaron that you can’t get your mind off), I agree with maxwell.