Can I really be charged with reckless driving for passing a school bus?

Yes, and many judges consider this to be a very serious violation. In Fairfax, I have heard judges say comments like "It's bright yellow, as big as a barn, and we put flashing lights on them. If you can't see a school bus, then maybe you shouldn't have a license!"  

I would not recommend trying to defend one of these without an Attorney. A good Fairfax County Traffic Defense Attorney will usually try to negotiate a reduction of the charge and keep the Reckless Driving charge away from a judge.