Don't be absurdly libertarian here.
You and I could each make a list - though perhaps different in content - of stuff paid for by taxes that doesn't suck and for which people would pay for if called upon privately.
The notion of "taxation being theft" is provocative if we're considering creation of a new social group, municipality or larger collection of people.
But in reality, each of us as adults are aware, or should be aware of the taxes pertinent to our individual communities. If we freely choose to live within these communities, we are agreeably consenting to participate in the associated taxation.
Not to say I don't encourage the peaceful and civilly disobedient hiding of revenues and other evidence that triggers various taxes. But once you've exhausted any and all such covert methods - then give. And be thankful our various governments don't actually send out armed collection agents who can seize your person or property without due process.
Obviously an issue costing a buck or two per capita in a single city is not going to be the poster child for libertarianism. And yes, if you take away taxes, some of that money would still be paid in some form or another for similar services. But consider this ...
You knock on my door offering me a service. You are 99.9% sure I will accept your offer, so rather than waiting for me to say I accept and pay you $50, you just snatch $50 from my wallet and say you are giving me the service whether I like it or not. If I don't like it I can leave. Then you argue that you did nothing wrong because I would've accepted the service anyway.
Well, in my crazy world, that's not how it works. Every time a government decides to spend my money, it's the exact same thing. Of course there is no time to ask everyone for each transaction, but that's only a practical matter. It doesn't change the basic demeaning and unethical nature of the action.
Still, in order for the world to function, a practical compromise must be reached. In a world where there is a high respect for individual sovereignty and dignity, that practical compromise is reached when the government gets involved in the fewest issues possible. There has to be compelling justification before the gov't gets involved in anything. If in doubt, the gov't doesn't do it.
So back to the micro issue of the day, I don't see compelling justification for the gov't to get involved in motivating students to do well in school. That doesn't mean it's a bad thing, just that it's not one of the govt's responsibilities IMO.
As for being thankful that the gov't doesn't send out agents, that's equivalent to being thankful we don't have communism. I am thankful for that, but those thanks are directed to the creator who made the world such that communism is a failed paradigm, and not to any set of human beings in authority who are somehow exercising their benevolence towards me in their own minds.