would an on the spot test change all of our habits?

http://articles.philly.com/2012-05-1...e-health-tests

like the pee on the stick , but a scrape on the gum,

That seems ripe for inaccuracies. Even blood tests give you false positives.

Also, is there a reduced rate for the 20-minute wait time?

I don't think it would change the habits unless a positive test result was encountered. People tend to happily live in blissful ignorance of the risks in this hobby.