I don't object to bringing a dog into the school but I do object to the children being lined up and searched - whether that searching is done by nose or by hand. For the reasons stated upthread.
I also think there is a wider conversation here around general policy around drugs in the UK and what is the best way of dealing with people who are caught in possession etc. Many people have argued for years that criminalising such an enormous % of the population undermines the authorities. That is all probably a matter for a different thread though.
I suppose that children will experiment and do stupid things - in my class at secondary school by the end I would say it wasn't more than a handful of children who hadn't tried drugs. The part of the country I live in has a lot of casual drug use (or did while I was growing up) and the people have gone on to have perfectly normal upstanding type lives. Is it appropriate to react with removal from mainstream society to what is in some areas rife but fairly harmless? Is it appropriate to apply the same measures somewhere like here as an inner city area where it's often a different picture with children being involved younger and gang aspects meaning an entirely different picture? If you're looking at children who are in a culture with a healthy dislike for the police (for valid reasons) how is lining them up in school (where they might hope to get away from that) going to help? You're saying "out of school, in school, because of who you are, where you live, what you look like, we think you're likely to be a criminal". Not good for social cohesion etc.
I think this is more complex than just zero tolerance, line up against the wall, you will be searched now.
Whole thing makes me uncomfortable and in areas with problems with stop and search it's just really not good.
Like I say, dog in school having a general snoop around, for me, OK.
Lining the children up for searching is, for me, not on whether it's a search by nose or by hand.