It's not tampering if the postal service or other government agency does it. It's how they look for drugs like fentanyl or other illegal things in international mail, similar to how when flying on an airline they'll even cut off any locks on baggage to search luggage. Typically to clear international customs there has to be a declaration of what's in the package submitted. I've had to submit customs reports for even just binders full of paper and technical documentation for work before. If there isn't these customs decorations, they'll open it to figure out what's in it. This is typical customs protocols and has been for a long time. I'm honestly surprised so many shipments of medications from somewhere like India have been getting through so far the way it is.