Well, in this case, if the LBS included a check back for free to see if the cable stretched and REI did not and one was required to pay again, the cost for 2 services at REI would add up to half the cost of the one service charge at the bike store in question.
I'm glad REI is here, it is now a LBS in our neighborhood. I'm feeling less warmly toward the original bike store given several recent experiences (I won't rant about them all) that include catching them at things like downgrading the saddle my new bike is supposed to come with and then charging me extra for the saddle they put on it.