Eric, your answer to Ray's answer doesn't really answer the question. The place where it connects to your neighbor's pipes in some buildings might be only three feet away, and all inside the common wall of a building, or it might be 100 feet away after travelling through a lot of dirt. If the latter than your risk might be similar to that of buying a house, where getting a sewer scope is generally prudent.
As others have mentioned, if the building itself has problems with it's main sewer line out, then that is an association issue, which has implications others have mentioned adequately. Note though that even with reserves, it would still be better if the association didn't have a $10,000-20,000 maintenance issue pop up. Not many buyers would check for such conditions, however.