One of the things that I have found that people end up losing the most frequently when traveling is their rather expensive mobile phones. This shouldn't come as a surprise because these tiny devices are worth a lot of money, relatively, and are a prime target for theft. Tourists are also prime candidates for this sort of targeted theft for obvious reasons such as not knowing who to report it to and in most situations, not speaking the local language.
It isn't very difficult to prevent the theft of your phone while traveling but you just need to remember that while most of the world is a very safe place to travel to, petty theft such as this is something that is very common. The devices are very rarely recovered and since most of us put so much of our life into our phones, there can be a lot of important information inside that cannot be replaced.
It isn't that difficult to prevent being robbed though, if you just use some sense.
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In most parts of the world where it is rarely cold a common method of stealing phones happens when people are behaving like "phone zombies" and this is something that I believe most people are guilty of at some point or another. They'll be walking around with headphones in, staring at their phones, and be very unaware of their surroundings. If you are clearly a tourist, this brings about the attention of motorbike phone thieves. They travel 2 to a bike, pull up somewhat slowly towards the person who is completely unaware of their presence due to their sensory blackout, then simply snatch the phone out of your hands and then speed away. By the time the victim is able to tell anyone that cares about it, the bike and the phone are miles away.
The "find my phone" apps aren't going to help you very much because the perpetrators are very aware of the fact that this technology exists and of the dozens of people that I have talked to that have tried to use this method of retrieval, none of the have ever gotten the phone back, let alone busted the criminals. They have phone technicians that will quickly reset the phone to factory settings and then the tracking apps will no longer function.
These phones are later re-sold at used mobile shop stores that appear in public shopping areas all over the world. It is a rather huge industry actually.
There are very few things so expensive that people carry around so haphazardly and the only thing you have to do is be a bit cautious when walking around. For one thing, and especially if you are alone, don't wander around with your phone in front of you, constantly looking at it. I know that GPS maps are very helpful but honestly, do you need to be looking at it the entire time in order to get where you are going? There was a time when we had to remember directions in great detail in order to get somewhere so certainly people can still do that.
It is just a good idea to keep your phone in your pocket until you actually need to use it and then when you do, be aware of your surroundings. If you are in a developing country it is a good idea to step away from the roads when you are going to use the phone at all.
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Another mistake that people I know or have met have made is to become too trusting of their surroundings and simply leave their phone sitting on a table while they go to the bathroom or play a game of pool. This might work out just fine in your home country but this makes theft extremely easy for walkers by. I met a guy in Asia once that left his wallet AND his phone sitting on a cafe table in order to use the restroom and while he returned to an empty table. This was profoundly stupid and when he demanded to CCTV be reviewed it showed a guy with a motorbike helmet on to conceal his identity calmly simply walked up and took the two things while his buddy waited at the curb. They didn't even speed away.
According to people I have met in the criminal underworld while traveling abroad is that a $1000 phone can be quickly fenced for around $100 if it is in good condition and that is exactly what these roaming thieves are looking for. This is far more money than they would make in a day from a regular job so while it is sad, it makes sense that they would do this instead. It's not like the police catch any of them very often.
When the people I know did report the theft to the police most of the time the cops just give them a piece of paper for them to submit to their travel insurance company - which is something else that is pretty important when traveling for this, and many other reasons.
I'm not trying to say that foreign countries aren't safe. In most ways I feel like countries that we think of as being dangerous are a lot safer than my home country of USA. However, there are certain crimes that have no bodily damage such as phone theft that happen a lot more frequently in them because the police are very unlikely to ever even try to follow up on them: They simply don't have the time or resources.
So be smart, be smarter than your smartphone, and just use some extra caution when traveling. I've been doing it for decades and have never had my phone stolen. I've also met many people who have had their phones stolen. Maybe this is a sign that what I am doing is working.