Taking over a lease.

I am considering buying a newer car, and I am wondering if its a good idea to take over someone's lease payments.

I have noticed there are some people who have leased a car, maybe just a few months ago and want to get out of the deal. They can't take it back to the dealer without taking a big financial hit, so the advertise for people to take over the car and payments so they can just walk away.

Is this ever a good idea?
Has anyone here done this?
What kind of paper work is involved......a new lease agreement with the dealer, or assume the existing one?

I know you are dealing with a used and possibly abused car. Also current wisdom suggests that the car is likely worth a bit less than the amount owing on the lease, unless the previous owner put a big down payment on this.

Thank you for your input.