Definitely not a question I have heard before, I like that. As far as your questions goes, there is always a chance. In most cases information regarding the property can be found on wake.gov website. If you need further help, contact a qualified RE Agent who can assist with that. However, be prepared that even with assistance, you might not find the answer to your question.
If you are purchasing raw land or a lot by itself, not part of a development, then I would definitely hire an agent to act as your buyer's agent and have them do the research. Any agent involved in land should know where to go and how to find out whether or not there is / was a cemetery on the property.
This is an interesting question that I have never had asked by a buyer. There are laws that govern cemeteries, (http://cemeterycensus.com/nc/wake/index.htm) in N. Carolina and typically older cemeteries that are primarily used by a family will be protected by the deed and will not be moved. You can go through the register of deeds website and look at the plats for the land which I have seen reference cemeteries, (http://web.co.wake.nc.us/rdeeds/). You could also discuss this with the builder and/or developer of the subdivision to see if they can give you more insight into the history of the land. That said, there is always a chance that an undocumented grave site could be present any you were to purchase land and you can only be as thorough as human records allow.
Hope that helps.