The experience with mine is that a couple of times a week, she has open knitting, in other words, no charge, it isn't a class, just an unofficial stitch 'n' bitch session. To think that every single person would buy something every single time would be nuts!-- but I would guess that every single person has purchased something from her at some point or another, and most of us take classes occasionally. But some don't, and as boo1 said, no one seems to care. As the others have said, it makes the store look busy and popular and you'll probably talk about the store to other people, and maybe even occasionally spend some money there. And you're not costing the shop a single dime by sitting there, knitting! So the owner would be crazy to give you a hard time, and I would go and just knit and introduce yourself and enjoy! If it eases your conscience, then maybe stop at a bakery first and bring some cookies-- believe me, no one is going to resent you being there for that:) .