I told my sister not to offer water to delivery person

This is not a hate post, but awareness post. My sister who lives in Mumbai is usually alone during the day, with her toddlers. I saw that after receiving deliveries or groceries she said thank you to the delivery person and offered if they need water to drink. All of them said no and nothing bad happened btw. But I told my sister not to offer water to unknown people anymore. This day and age is not the same as 10-15 years ago when people used to travel far and wide without rest and we used to offer water out of kindness. Nowadays there's a possibility that when you turn around to fetch a water glass, the delivery guy might grab you from behind! Yes ik not every delivery person is like that, but why take the risk? These days nobody goes out without a water bottle, or if they are really thirsty, they can afford to buy a small water bottle. But knock on wood, suppose somebody had an intention of attacking, then what? What would my sister be able to by herself with nobody to help her but her toddlers? Yes there are security cameras where she lives, but that's not going to stop harm from coming in anyone's way, it's just going to lessen the chance of it. Not to mention the trauma it will cause to the victim, no matter who it is. Be safe everyone. And be careful.