In real time, I've solved 2 puzzles with no letters revealed during normal rounds in my 40 years of watching WoF.
Since the advent of DVDs, I always pause on the final puzzle to see how long it takes me to solve it after the chosen letters are placed. In this case, it took me ~30 seconds. Obviously, I would've lost like everyone else.
That said, I instantly saw the incorrect "pathway", which I soon resolved to "walkway" but had the most trouble with "gravel".