When you are working in a sales department, you are working in a perilous department.Any institution that manages a lot of cash is always a magnet for thieves and other wrongdoers. Perhaps it is just human instinct to take advantage of people and get as much wealth as they can. I am not saying that this goes for everyone, but pretty much everyone wants to earn more money. It's just that some people's ways are less than what's acceptable.
Anyway, since crime cannot be completely eliminated, thanks to greed and all those philosophical stuff, we have to find a way to make sure that we will never be the victim of these thieves. True, we cannot be perfectly sure that we won't be a victim, but doing something about it already makes a lot of difference.
So how will you avoid the thieves or outsmart them? Put yourself and the cash in some secret room, buried hundreds of miles from the surface of the planet? That sounds too top-secret to me. You're just working with money! Should you seek the protection of hundreds of soldiers? That would probably be the case if you are constantly working with someone very important. Should you feign when thieves are already there? That does not seem to be the smartest of the ideas.
What Office 1000 thought of is fooling the thieves by hiding the money in such a way that it cannot be noticed by thieves. In case for small cash, this cash box disguised as a book might be good enough to settle your requirements. With the realistic-looking book cover, there is a little chance thieves may rob the valuables out of it.
Now that is something clever.