Yes, airport security (such as the TSA in the US) can and will open checked luggage for physical inspection if something suspicious appears on the X-ray scan. If your bag is selected for a manual search, officers will open it to verify the contents. If you use a lock, it is highly recommended to use a TSA-approved lock, which allows security to open the bag using a master key without damaging the lock or the suitcase. If a non-approved lock is used and a search is required, security is legally authorized to cut the lock. After a physical inspection, a notice is typically placed inside the bag to inform you that it was searched. This process is standard worldwide to ensure that prohibited items, such as explosives or flammable materials, are not transported in the cargo hold.