The questions/issues that agents need to raise with sellers:

1. Did you inform the insurance company that the home is vacant?  Remind them that there is an added cost for this, however, the liabiity of having a vacant house is great for the insurance company and the owner.  Not informing the insurance company can void the policy - so if there is an accident on the property or damage - the owner may not be covered.
2. This might be a good time to speak with their insurance agent about some additional liability insurance.
3. Someone needs to check on the house regularly and actually go inside and check for problems and walk around the house and yard.
4. If it is winter, consider winterizing the home.
5. Someone should be responsible for picking up flyers, local newspapers, watering plants, et.al.
6. Lawns and Gardens need regular maintenance.  Have they made arrangements?
7. Is the seller willing to pay for staging?   Who would you recommend?
8. Have they considered renting if they can't sell it?
9. What hours will the house be shown - keep normal hours - 24 hours creates dangerous situations.
10. Someone needs to check that the doors/windows/garages have been secured.  Yes, we'd like to think the other agents do this.  I toured a vacant house last week and called the agent to tell them someone not only left the backdoor unlocked but wide open.
11. Utilites need to be left on for safety, but they may want to consider the pros and cons of turning off the water.
12. Who will check that the burned out bulbs in the light fixtures are replaced?
13. If the house is on the market for some time, other issues like furnace filters need to be considered.
14. How will additional cleaning and maintenance of the home handled?
15. What should be done if there is an emergency and the owner is unavailable, is there another person locally that can make decisions (get it in writing).
16. Are there pest control issues?  How will they be handled?
17. Has all the trash and extra furniture been removed from sheds, attics, crawl spaces?  How will that be handled?
18. How will repairs be addressed if they come up after a home inspection?  Who will meet the repair people and who will be available to authorize work?
19. If the sellers are out of town, are they attending settlement?
20. How will you get the offer presented?  What are the logistics - email, fedex, mail?

Vacant homes can be quite a burden, but if you don't discuss these issues ahead of time, you might wind up being the person who is taking care of these issues and bearing the stress of the responsibility.