The US check system is quite outdated. It was not designed in a secure way in the first place. My mother still pays stuff through checks, I guess because she can’t get used to the idea that she can pay things like a mortgage online or automatically and does not have to physically drive to the bank every month. I suppose at least she does that rather than mailing it.

The victim even walked the envelope into the US Postal service office. That certainly reduces the number of people who would be handling it before it was stolen.