I think that uniforms and all the searches that you list here are different sorts of issues: the searches, detectors, et al. . .communicate, as you note, suspicion of covert activities, that the students are hiding something. Uniforms aren't that way: you're either wearing it or you're not. And if you're not (or have manipulated it in some way), then go home, take a 0 for the day. And come back when you're ready.
Lesson #1 learned: if you want to break the rules for something as small and petty as showing a little more leg, then you deserve to suffer the consequences when they're small and, relatively, harmless. Lesson #2 learned: sometimes you have to follow the rules, even if you don't like them. Honestly, the whining about I hear about having to wear uniforms reminds me of something my 5-year old said this morning: "But daddy, I really, really, really want cake for breakfast! Cake is so yummy!" That may be so, and when she's and adult she can eat cake for breakfast if she wants, but today, it's wheat toast and a banana.
I think, Auntie, that your concerns about school searches and similar paranoia, established after the Columbine shootings (which to me, did more than any political policy to change the structure and tenor of US education) are a truly severe problem. And the US needs to lighten up (a lot) on the prison element of school.
As a side note, I'm not all crazy about uniforms myself. I just posted the question because a personal observation got me thinking about the connection between dress standards and education.
Here it is: In the small town in which I live, there are two schools, the larger public school, and the smaller Catholic school. The Catholic school doesn't require uniforms, but the dress code there is MUCH more stringent and enforced than the public school. And, the education and overall moral and social preparedness of the students at the Catholic school is leaps and bounds beyond that of the public school system. (And this Catholic school is light on the Catholic, really light on the Catholic, non-believers can opt-out of Mass, do independent projects during religious class. . .).
Anyway, my kid is in the public school where I see the most slovenly dressed students using foul, inarticulate language and rude, rough behavior. Now, I'm no fool: I know there are a lot of socio-economic issues at work here too that far outplay role of strict dress code. But, I wondered, surely the dress code is doing something, right?
Maybe it's doing nothing, but it doesn't seem that way. At the very least, it seems to establish a more consistent, studious air about the place. . .a respectability that affect a lot of things indirectly. I've never claimed that dress codes or uniforms are problem solvers; in truth the large issues that you rightly bring up here cannot be solved by one major change, but by many, many small adjustments to mood, structure, curriculum, and (ultimately) the social values of the citizenry.

