Safety during the travel is probably the main concern of travels no matter if they are going solo or with family or friends. But safety of your luggage is also extremely significant, without your luggage, you are basically a homeless person who has nothing in a strange city.
A lot of companies have realized this need for safety and have development brilliant products to help traveler keep their stuff safe. Messenger bags are known commonly among the industry because of their protective mechanisms. Even the very basic messenger bag would at least have a built-in locking mechanism for the zippers. But if you are trying to protect heavy cameras and laptops, you will have to take further steps, like seeking a slash proof bag with at least 2-3 locking mechanisms.
For unknown need, keep at least one or two locks with you, you can never know when you might need them. Consider taking a safety alarm rather than pepper spray. Pepper spray is illegal in a lot of countries and isn’t allowed in a lot of airports.