no but seriously, there is this elastic band grippy stuff you can buy and sew at the top of the bustline. it sticks and it doesn't matter if you're sweaty or not. my wife used the stuff before. it works. the only thing is... well... after the wedding, when you and your Mr. get to being a little romantic, you're going to have a rubber band induced line above your bustline for a while =P
Depending in the thickness of your dress, do you even need to worry about tape? I got married outside at a vineyard in CA and I went au natural under my dress. It was great because the dress was fitted enough to hold me in and I didn't have to fuss with a bra, tape, etc.