Been lucky so far; never lost any luggage.
Also, I put the nylon straps, very tight, on the suitcases. Then use zip ties, very tight, on the straps, where they cross each other and under the suitcase handles. This keeps baggage handlers from rummaging thru the suitcase, unless the cut the straps and zip ties.
I know, a determined thief will still take the whole suitcase if possible.