You should take theft into consideration, but it shouldn't ruin or occupy your trip. Be smart, aware of how thieves operate, and just be careful. It is hard to imagine a clear morning in Zermatt, looking up at the stunning Matterhorn in the blue sky, flowers nearby in bloom, and someone next to you quietly muttering " I know that guy in the bakery is out to get my bags. "
Look at the posts reported here on FT.
Checked luggage appears to be more of a theft of valuables issue, involving a few bad apples in the inspection process these days. Three years of daily stealing by an inspector and his wife results in just being terminated with probation. My, my, what ruinous severity. Laughable.
One hopes that given a year or 5 in prison instead, that trending would dramtically diminish. And being federal employees, why not make said thefts a federal crime, to be served in a federal penitentiary like Leavenworth, Kansas ?
But the facts are that the luggage cases and bags are just rummaged through, and rarely stolen outright as they remain under the care, custody, and control of the airline once checked. That thief wants your Ipad, hidden cash, or packaged Rolex to fence as it is stuffed quickly into his pants, and not your luggage case.
Luggage in your possession and control is another matter. Unattended luggage, even for just a quick moment, can be stolen. Leave your your luggage alone on the curb, in a unoccupied car, or by your side at Milano Centrale train station for two seconds and it vanishes, very quickly. That quick panini or espresso diverting your attention just cost you your case and your clothes.
Same on the train down to Venezia, Roma, or Rimini: Keep your luggage in view at all times. Don't leave it out in the luggage racks in the aisle. Keep it close. I mention these examples for a reason.
I met two different couples, one from the US and the other Canada, who had this happen to them. One was ready to call off the month vacation they had planned and return home immediately. Everything looked negative, and the nice locals were all suspects. My wife and I talked them out of leaving, and helped both find replacment clothing, etc, which one does when these situations arise. We stayed in touch for a few years afterwards and they were most appreciative.
Again, there is no evidence that thieves discriminate by luggage type, colour, or model. No thief pondering " I think i'll wait for a new blue Sampsonite, or a Limbo today. " Think about it for a moment: A nice alu Topas would actually be a liability for any thief if it were reported stolen to the authorities, especially if the owner provided the serial Nr. stamped on each Rimowa case. These thieves also want the contents of your luggage.
Thieves look, create, and wait for opportunities, which distracted and jet-lagged travellers in unfamiliar surroundings can present. Make it impossible or difficult for them, or slow them down, and they lose interest.
When such an opportunity does arise, they move on the luggage immediately, no matter the make, colour or model. The big orange or pink case may get your attention at the airport or bus station, but the unattended case or duffel nearby has the full attention of the thief.
I like to think that a luggage case gets me to a destination with items protected inside that will allow me to either work or vacation there comfortably. By making it easier to inspect my belongings using a TSA lock all these years without incident, I have facilitated my own ability and that of others to travel quickly, efficiently, and safely. Theft is really secondary, and never an obsession.