Do you think teachers and bus drivers should be allowed to have personal stickers/flags..?

You can put anything you want on your vehicle (so long as it is not in violation of obscenity laws). However, you cannot necessarily park it where you want to park it. The school gets to determine what is on its own grounds. Having this vehicle parked in my driveway would make me very uncomfortable. If it was there every day, I would do the same. School grounds are not considered an appropriate forum for free speech rights - kids are allowed by law to wear t-shirts with beer advertisements or swear words, but must turn them inside out while on school grounds.