It would depend on the context in the storyline.
Some of my fav film scenes involved long dresses, such as Hound of the Baskervilles (1959), The Moonstone and the like. Granted, they were period pieces, but they work.
If someone wanted to use something more like a wedding dress, there should be some logic to her attire, at least for it to work for me. We could have a bride who gets cold feet, runs from the church or private manor where the ceremony is being held, ends up in a bog, and is rescued by her future husband.
Or, in the horror tradition, she could be a murdered bride come back to haunt the woman who sought to replace her, cornering the bad girl and gradually forcing her into the mire, following her in afterwards, where they both sink from sight. Pushing this further, the ghost bride could show up on the wedding night, chasing the bad girl out of bed (and in whatever state of undress she is in) and into the nearby handy bog, thus saving her man from the harm of being married to someone who killed the first bride, and likely plan to do away with the husband for his money. The new husband, of course, is blissfully ignorant of this, as he is in the washroom brushing his teeth at the time... (and conveniently off camera...)
That's my two cents...
