I read an online article a year or so ago (actually several articles) where a guy did a test in a swimming pool wearing waders and said he was able to swim about just fine with the waders filled with water, especially with neoprene waders. However, he said it was impossible to get out of the pool and suggested that if anyone doubted him to lay in your bathtub with waders filled with water and try and get out----impossible he said.

With this, he said that if you were fishing water that had any kind of a bank or if you were required to lift you legs in any way that you would not be able to get out. His conclusion was that you should always wear a belt.

I tried to post the link here but it was in PDF format.

Scott