I agree that hosts need to be prepared to provide something in the way of drink (soft is fine - can see bring your own booze) and if the party is of any length of time and during a mealtime some food should be provided, even if not all of it and requests for extras are made.
The key thing is to be very clear - about what is being provided and what you are asking people to bring. So saying for a BBQ, '. Please join us for a being and share BBQ. We will provide salads,puddings and soft drinks, and would appreciate it if you would bring your own meat and booze' is okay - because you are making it clear it is bring and share.
I do think that especially if you are asking people to travel a distance it isn't right to ask them to bring food which it is hard to transport or keep in good condition. If you are asking them to travel AND pay for accommodation, you really do need to make a decent offering of food......this is unless you are students,when no one has any money and things are different.
I recently went to a camping 40th. We all paid for our pitch. Host asked those more local to being a pud or salad (not those coming from a distance) and then provided vast quantities of meat and booze. Everyone was happy.
I have also been to cream tea parties - host invites guests for a cream tea mid afternoon. Lots of scones,cakes and cream provided, tea and probably Pimms too. Pretty cheap to host, but pleasant. Menus from 2-5 so not over a mealtime and only local guests.
It IS tight to claim to be inviting people a distance to a party (especially if it is done in a grandiose way with invitations and a sense of the largesse of the host) but then to not provide anything or only crisps etc.