Your math is wrong. You cannot determine who to search in this way beforehand because you think a certain group might have more contraband or crime. Aside from

Your math is wrong. You cannot determine who to search in this way beforehand because you think a certain group might have more contraband or crime. Aside from the trivial bypass you would introduce, that will additionally cause the survivor bias in your search statistics. Adjusting some proportion of searches to one group or another in this way will ignore the types of people in the group. What works from NYC->Las Vegas will be absurd according to your logic when applied to NYC->Florida retirement communities. It is drugs or bombs? The results will also look different in both scenarios. The correct solution is screening. I have news for you about drug smuggling, its the 21 year old who are caught. You should probably just let them have their MDMA. It is all destined to be absurd, however; in the movie theater hypothetical, searching some percentage of 21 year old men is uselessly ineffective. What is the ratio of movie theater attendees to movie theater shooters? It's on the order of homeopathy. The logic and methodology in this is so tragically flawed. > This kind of reasoning results in ... ineffective solutions (security theater) You missed the important parts.