Although laziness may often be a problem, I think sometimes it may also be inexperience, or just a lack of knowledge about the geographical area concerned - for example, distances within the UK are on a very different scale from some other parts of the world.
But it's the hijacking of large chunks of my ancestry that concerns me most about hints.
Distance is a very interesting conundrum once you get outside the UK... especially when you're talking Australia, the United States or Canada, all of which are enormous, but then if you don't know much how big they are, and the unlikelihood of someone having children born in both Melbourne and Perth (we're talking 3-4 hours apart by plane) or more complicated - children in both Melbourne and Mildura (Mildura, while in the same state as Melbourne, is 6 hours drive north-west) is going to be missed. And to be honest, I don't know the distances in the UK, nor do I always know which counties are next to each other! (I'm getting better at the ones in which my ancestors lived).
I suppose it comes down to a choice - I keep my public tree as accurate as I can make it, and hope that people notice the accuracy and at least attempt to amend their own trees so they're correct (that and my public tree has helped cousins find me). But then my ancestors are incorrect in so many trees across Ancestry (this being the ancestors who emigrated in 1839 to South Australia, and yet people have them having children in Sussex - they lived in Hampshire before they emigrated - in the 1840s and 1850s, at the same time they were having children in Australia.) I once wrote a message to someone pointing that out... which was ignored. I then simply gave up. If someone is silly enough to think it is possible to have children at the same time in both Australia and the UK, then their inaccuracies are in the end, their own fault.
While I'd love to help people correct their trees, I'm a bit of a philosophic shrug type person, I'll help them if they want... otherwise, there's not really anything I can do. (probably something to do with the fact that I teach teenagers for a living).
If it's going to be an ongoing irritant for you, then you're probably best leaving your tree private. If you can ignore it and want to help those honestly looking for information, go public. Either way you and your tree are within a message of someone who really wants that information.