If it were a one off thing, I wouldn't think much of it, but over the last year I've had around 10 rides from terminals to the Marriott, and everyone said they called after waiting for a while.

I've also seen some people trying to cross Hotel Rd. to get to it after walking thru the terminal B lot. Wouldn't recommend trying that now, as it's a lot busier since the new terminal A dumps out onto it.