Earlier quoted context omitted.
"Never attribute to malice that which is adequately explained by stupidity." https://en.wikipedia.org/wiki/Hanlon%27s_razor
Stupidity does not adequately explain why they are considering bringing charges of a "hoax bomb", or sent this letter home with the other students: http://www.irvingisd.net/cms/lib010/TX01917973/Centricity/Do... [PDF] Therefore, malice.
Remember the Aqua Teen Hunger Force "bomb" scare in Boston? The city rigorously pursued legal action to spare their police department the embarrassment of having wasted millions of dollars carefully dismantling DIY Lite-Brites.