McDonald's Sign: Thirty Minute Sitting Limit

We were coming back yesterday to Gainesville from Lakeland when we pulled into a McDonald's off I-75 in Dade City.  It was one of the friendliest McDonald's I've ever been to and the service was excellent.  There was only one problem with the place as I saw it: there was a prominent sign there telling customers to limit their visits there to thirty minutes.  Longer than that they considered as "loitering".  I've seen this sort of sign at the McDonald's in Gainesville which is on US 441 a block from the University of Florida campus.  What gives here? Isn't that sign something of an affront, essentially telling customers to pay up and then get lost?

My instincts tell me that, as long as you are continually getting up and buying stuff from time to time, these McDonald's managers wouldn't care if you stayed there the whole day.  After all, they try to bring in longer-staying customers with their free Wi-Fi and the espresso coffee drinks they offer, obviously wanting to siphon off some of those free-spending Starbucks customers (who tend to stay glued to their seats for long stretches).  The problem I see that probably prompted the signs is twofold:  sometimes people will wander into an establishment like a McDonald's just for a place to sit...many of these may be homeless.  That probably applies more to the Gainesville location than to the one in Dade City.  Also, students tend to camp out with their laptops and books and monopolize seats for hours...and some of them have the nerve to not even buy anything!  I often go out to places to study, and I usually take well over thirty minutes there.  But if I'm done with what I had initially purchased and it looks as if I may need to stay there a little longer, I'll make a point of going back up to the counter and buying something else.  That I thinks soothes the worries of anyone working there who thinks that I am trying to take advantage of their seating hospitality.  After all, they're in it to make money and have a right to ensure good available seating for paying customers...