As Dr. Peter Venkmen once said, "I have more than two grades of laundry than just clean/dirty; there are many subtle levels."

Security, whether traveling or at home, is rather like a balance scale, with risk and difficulty on one side, and reward on the other. One doesn't need to bottom out the risk/diffuclty side to be relatively secure, one merely needs to tip the scales enough in that direction to discourage the most common types of theives.

Simple example - putting your small valuables in the hotel room safe, and locking your laptop with a steel cable to some fixed object in the room, make it too time-consuming (thus risky) for most hotel theives to bother with.

Sure, they can carry a pair of bolt cutters into the hotel and use them to cut the cable. But they usually don't. Sure, they can carry electronic gear or steal master keys to open the safes. But they usually don't.

Theivery by housekeeping is very common, but housekeeping theives generally don't bother with the safe or with a locked-down laptop.

Why not? Because the room next door may have a loose, unsecured laptop, phone, or jewelry box that they can take in a few seconds at a much lower risk.

Most hotel theives are dine-and-dash opportunists - they slip into a room, grab whatever is loose and exposed, and slip out again. They're usually not interested in spending more than a minute or two in the room, because the longer they're in a room, the more likely they are to be discovered by someone who knows that they're not supposed to be there (such as the legitimate occupants).

So, you can't make yourself completely secure. But you can make yourself less a less attractive target by relying on methods other than the door lock alone.

And it should go without saying that, whenever you're actually IN the room, the deadbolt, chain, and any other mechanical fasterner the door might have should be secured at all times. Not only will it prevent theives from getting in, but it will also prevent unwanted intrusion by hotel staff or other guests who may have been given the wrong room key accidentally.