I never allow bottles either. I'm surprised that parent's still allow this at home. Aside form the fact that it's bad for their teeth it can also cause ear infections. I'm amazed that parent's still don't know that your nasal throat and ear canals are all connected. Milk gets way back in the throat and can get into the ear canal and cause a bad ear infection which equals= a very upset and sick child on anti-biotics that the parent tries to dump on us!!
I simply do not allow it and snip it in the bud right away. No water, no milk, no liquids period.