Two points worth making:
1. In my experience, there is more suite shop/treat shop (whatever it's called) theft than you think. As crazy as it may seem, a lot of guests, especially weekend/transient, assume that it's all included in the room price to be taken or simply they don't care and will take their chances that nothing is said. With times being as bad as they are in the industry it wouldn't surprise me if management has the staff watching every nickel and dime in every way possible. IMHO, the desk clerk made an embarrassing mistake and hopefully they apologized for it. Stuff happens.
2. A lot of hotel's camera systems are weak/bad/inadequate or nonexistent i.e. are there as a "visual deterrent" but they don't actually record anything. At the Hampton I work at now we have five "cameras" on the property but none of them are capable of recording anything and I've also worked at a Homewood Suites where the camera footage could only be retrieved via our corporate office which was 1500 miles away and they only did it via a subpoena. The idea that you're going to just ask them to check the footage right there or in a timely manner, while possible, is not likely happening.