[Varyon]

I think technological means of detection are probably a better bet (and I'm pretty certain that's also included in the Super modifier, as a subset of mundane countermeasures). 1,000 sniffers would be around 0.1% of the total population of supers in present-day USA, which doesn't sound like a lot until you consider that not all sniffers are going to be inclined to work in this manner, and of those that are the private sector is likely going to give them far more lucrative offers (for security jobs and the like) than the government can. Unless power detection is one of, if not the, most common superpowers, the government is likely to have trouble getting those 1,000 sniffers (plus the ones they need for security details and jobs other than constantly having to deal with kids; I'd imagine they're in high demand amongst the Secret Service). Perhaps a system where the students are scanned as part of mandated regular health checkups, and those that give a positive are required to go to a specialist (who could be a sniffer, or just someone with better detection equipment), would work. The specialist would be able to confirm the cheap school machine's reading (or determine it was a false-positive) and possibly analyze the student to determine the nature of his/her power.