Et in Arcadia Ego: Part 2 - S1-E10
Trivia: The ships that Riker arrives with are all identical, explained away with the line "I've got a fleet of them at my back." That line's delivered without seeing Riker's face, because it was recorded afterwards. The effects work was only completed shortly before the episode was released, and they didn't have time to create a variety of ships, leading to this "shortcut."
Chosen answer: My guess is that they go to 1 place and they can't chose where to go. Like a highway without exits, you just end up where the highway stops.
lionhead