Great heads up about looking closely at the safes prior to putting valuables in them. I'll be sure not to every trust a safe where there's a visible battery compartment because of your post.
Unfortunately it makes little difference if there is a visible battery compartment or not if a theif has copy of the master key. I have in room safes at my home with the battery compartment inside but there is still a visible keyhole for those that forget their combination or if the batteries die.
We put them in because some people wanted them, I personally hate them as they scream to a crook that that is where the money is and often, as mentioned, they are not secured properly if at all.