First, it is called express delivery because it is "fast"! In order to deliver it to the customer early, the courier brother appeared the phenomenon you mentioned. Of course, the security guard is someone that the unit can trust.

Second, people are curious, and safety is no exception. Especially when you are not busy, it is understandable to touch things casually.

Third, it is polite for security guards to greet themselves when they pick up their own pieces. Feel free to answer a few words. Better than pouting, right?

Nothing, nothing! Don't mind too much.