Sorry, you are incorrect on this one, at least on newer Android phones. You can track android devices from My Account on google.com. No software need be installed on the actual phone. I'd also argue your use of the term "spyware" for software intentionally used by the owner, but that's probably just going to distract from the conversation - oh well.
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Seriously, what do you teach and at what level where the kids in your class have all this need to kill time? I'm trying not to be judgmental here, but... really?