Personally I'd not paint it, a bit of paint running isn't worth a spoilt relationship with neighbours in my view. You never know when you'll need them and nothing worse than not getting on. However if you do decide to go for it I'd do it with care to make sure the paint doesnt run, if you do a few thin coats rather than on heavy coat you might avoid it bleeding through. It's worth considering you may have to approach them one day to ask them to do, or as the case may be, not do something that you'd prefer they didn't xx