Concern group says women face common threat of nude photos taken without their consent
https://www.scmp.com/news/hong-kong/law-and-crime/article/3074103/concern-group-says-women-face-common-threat-nude
These images would be taken individually in Hong Kong. But in Japan, some groups do the similar things collectively. If you are female and spoken by a handsome stranger in downtown of big cities in Japan, you will be involved in incidents like this