my situation might be a little different than others, as it's just the wife and i. very few people even know how many firearms i have, and outside my wife, father and brother, no one even knows where they are located within my home. out of site and out of mind. now if a burglar were fortunate to gain entry to my home, (very unlikely with the dogs in the yard!) and were allowed a couple of hours to try and find them, (again unlikely with the inside dogs!) then yes, they might be able to locate them. i keep the serial numbers recorded in several places, including a copy with my insurance agent, in the unlikely event they were stolen.
i have to agree that when you have firearms in the home that securing them from those who shouldn't have access, such as children, is more important than it's access for an invasion.