I would be pissed if my LHBS charged for the crush too. I mean WTF, I just bought this from you, and now I am getting charged again?
But my LHBS store lets/makes (I prefer it this way) you pull the grain, crush and bag it. When you get to the front, they ask what you got, and that's it. Also, the crush wasn't that good for a while, so I would run it thru twice, but they seem to have adjusted it, so it is much better now.
I don't think too many people take advantage of them by stealing a extra grain. I have seen/heard of some people who would come in with bags they bought somewhere else, and crush there, buy 2 oz of hops, and walk out. I think that is pretty low. I think as long as you buy it there, you should be able to crush it there gratis.