My trailer ( funfinder 189FDS ) has a schwintek slide. It's a flush floor design, so yes the inside edge is unsupported when it's pulled in retracted. However, I have looked under the carpet flap, and that piece that is the inside edge is some sort of rigid, dense plastic that is actually rather thick and seems to be pretty stout. Pushing down on it as hard as I can from there with my hand, I can't hardly flex it at all. I use my dinette regularly with the slide in. However, I can see that it would make sense to not overload that area while it's in/unsupported. I am the only one in my trailer, so I'm pretty gentle on it. I suppose if I were going to use it a lot retracted with several people, then it might make good sense to make a long thin "support board" to slip in place under that edge.
