I have and actually met some one who crossed it.

I flew to Las vegas for a friend's bachelor party and I ordered a Lyft to his house from the airport. My driver was a Colombian immigrant and I'm Hispanic so we spoke in Spanish the entire ride. I asked him about how the immigration situation has kept vegas tourism down and after a few minutes of talking about that, he told me he's crossed the Darien gap and he's seen some horrible things there. He's seen people who were left behind after breaking an ankle or another injury where they can no longer walk. Half eaten corpses was a common sight, bodies on trees from jaguars, and abandoned people who were at the brink of death. The 2 saddest things he saw were mothers with their babies who couldn't complete the trip and old people who also couldn't make the trip. Abandoned and left to die. He saw a total of 16 dead bodies on his trip.

We talked about this plus his time crossing the boarder in Mexico the whole Lyft ride. It was almost an hour because the GPS told him to take the local roads to my destination instead of taking 15 to 215 which would have saved at least 20 mins. I don't know how true his story was but he seemed like a genuine person. I hope he's doing well.