If they are taking up seats and not eating, my chance of getting a seat is reduced.
This isn't just being bitchy. Where I live/work, there is one area with a concentration of cafes. At busy times (and not just lunch, it is a busy area), it means that - frequently - one cannot get a seat in the cafes. When I go on my own and eat or have a coffee, I take up less seating, space, and, often, time than when I am there with DD. If I am using multiple seats and (perhaps although I admit not necessarily) for a longer time, that does affect the people around me as well as people who would like to come in but find the cafe too crowded.
Adding to this problem by using a space when not providing a reasonable level of custom seems wildly inconsiderate to me. A reasonable level of custom is I admit a vague term, but I think most people are capable of figuring it out. If you are there with three kids and you buy one coffee and serve them a packed lunch, that is unreasonable. If you buy yourself lunch and share it out with a baby, or breast/bottle feed a baby, no one most people would consider that reasonable. If you have a child with special food needs and you can't meet those without self-catering, again, that is reasonable. I kep coming back to this thread in part because I feel that a reasonable position - one based in common sense and consideration for others - is somewhere in the middle and I resent the way that some people on the thread are obscuring that.
Someone compared it above to bringing your laptop to a cafe and not ordering. I think that is inconsiderate, too, and I think most reasonable people know, inside, when they are taking the piss. I do a lot of my work in a coffeeshop. I alos frequently take DD to coffeeshops. I am not unaware of the difficulties of both activities. But I feel like the 'cost' of using the space is that I have an obligation to purchase items and to also be mindful of other people who are sharing the space.
In some of (again, not all) the responses on this thread, people have defended the practice of taking multiple children to a cafe and feeding them there, while the adult buys, for example, a coffee. This is probably the most extreme example, sure - but some people are saying that it is not my business if any one wishes to do that, for reasons of economy, preference, or convenience. I am merely saying that it is, and that I am certainly within reason to post here that I think it is wrong and inconsiderate without being shouted down for being 'insensitive' (insensitive to whom? assholes? I've already TRIED to make it clear that my complaint is not with those who have a legitimate medical reason for self-catering) or being told that it is not my business how other people conduct themselves even when it does affect me.
And there I go again...I really must go do laundry.