No, there isn't. The hypothesis they were testing was whether a superfluous apology would increase the likelihood of strangers behaving in the desired manner. All they proved is that making a lead-in comment had this effect. We have no way of knowing whether it was because the lead-in comment was an apology, or if a broader range of comments would have had the same effect.
Saying there was no proper control condition is flat wrong. There is a control in the study that would falsify the hypothesis that they were testing.