With larger birds such as African Grey's, there is a really high risk of injury to the bird if they are allowed to grow up flying inside a house. Young birds do not understand glass for instance, and will attempt to fly into it, ultimately doing harm to themselves. To offset this, the non-permanent wing clipping is employed to prevent them from taking flight. This doesn't prevent gliding, however, so they can still leap safely off ledges to the floor to get around. Once they're older, you have to take into account that the nearly or fully grown bird has never flown, so you keep clipping the wings as they don't know how to use them.
I've never owned a Parrot but I grew up with one and my parents opted to not clip his wings. The net result was a lot of snapped feathers and a bird with neurological damage from running into things full tilt. Not pretty.
However, Hernandez and other students only qualified for the magnet school by having good attendance, grades and test scores in the first place.
I'd also like to point out that schools that really need to have truancy addressed are the poor, inner city schools that can't afford a technological solution to their socioeconomic problems.
The clearest way into the Universe is through a forest wilderness. -- John Muir