If they're disguised as black holes, then they must have the same external characteristic as a black hole: "you can fly in but you can't fly back out." This would likely also mean that even if you flew into an indistinguishable object that looked like a black hole but might be a wormhole and successfully reached another point across the universe, you wouldn't be able to exit to find out where you were at the other end, or be able to return and exit back to your starting point?

This travel system must be provided by the same people who run some of our airlines.

John