There is a window of opportunity for anyone whom has a mind to take what they want if they so desire.
We don't have a booking in book for returns & we have no cameras either, customers walking through doors willy nilly, packets went missing last year of mine.
Locker telling the gaffa I was not bringing them back, told them i was, they said your not otherwise they would be here???
Now I book everything back in myself on a note book with tracking numbers the lot, guess what since I been doing that NOT ONE of my packets has gone missing.
Told gaffa there was a thief in the office & that if my packets go missing again, on my new system I will be calling the security helpline/ IB myself!!
People if this is happening to you, cover your arse make a record of everything you bring back, it may take a few minute of your time but it is well worth it.