When did this policy go into effect?

I'm asking because my mom and I were not allowed even allowed to leave SFO airport in Dec of 2017. We were headed to Laos, but had two layovers in 2 cities (Qingdao being one of them). We were denied access and were not able to fulfill our trip. We had to cancel our trip, which ended up costing us $1000. We had our passports and photos to make visas once we got to Laos.