I have a similar ratio, but I would welcome a time limit. Web I go its usually just to hang out for a bit, read a book, and maybe comment about the passing customers on Twitter. But if it is one of those one or two in ten times I plan to stay and there are people at every comfy chair with laptop plugged in, I'll leave without buying anything. So I guess we have opposite philosophies there. I don't think it would at all affect my patronage when I want a coffee to go.