Sounds as if you've reached a rational understanding with customers and are willing to walk away if they won't co-operate. That's probably the best advice of all here.
I'd agree that local tables aren't a good idea in a distributed or large system, or if a customer of any size is capable of hosting a C/S database and managing it themselves.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
