About once a week one of my inspectors or I run into an electric panel somewhere in a garage or laundry area that is inaccessible due to personal storage. Often times, permanent shelving being placed over the panel face so that it cannot be removed or the door opened as on the case below. Some licensed states require us (inspectors) to open and inspect the panel for deficiencies.
There is a huge safety concern here. First of all, panels need to have unrestricted access in the event of an emergency.
Secondly, it will save your seller the expense of having a licensed electrician come out to evaluate the panel or the expense of a trip charge by having the inspector come out again to inspect this item.
When you are doing your walk-through during your listing, take a moment to see if this condition exists and inform your client accordingly. You will look like a genius!
This posting and the contents herein is the intellectual property of Michael Thornton, CEO of The Complete Group. We provide the highest quality service in the areas of home inspections and videos/photography for the web, corporate, businesses and the real estate industry. Complete Home Inspections, Inc. and Creative Video Concepts serves the Brentwood, Franklin, Nashville and the area surrounding Davidson and Williamson County TN. This post is a contribution to the ActiveRain Real Estate Network.

Great advice for safety reasons in general! Besides access to the electrical panel, the seller should make sure that other areas are accessible such as attic crawl spaces, hot water heaters, etc. I remember looking at houses and having such a hard time getting to some attic areas (which was important to me). I would not consider the house if I couldn't see the attic.
(Thanks for commenting on my "Full refrigerator but nothing to eat" post. I'm up for pizza and beer too!)