Since it was just the two of you, that sure sounded egregious. But again maybe they expected you to notice them seating others and walk up to the desk.
I visited an Olive Garden several times over the past few months. I always went to the bar counter. Several times they gave me free items. Once they forgot the chicken on my Alfredo, and served me both the original and the replacement while billing only for the original (cheaper, no chicken). Once they apologized for not having a spatula for my pizza because customers apparently kept stealing them and they were out. I tipped a normal table-type tip at the bar, which is more than they usually get at the bar. So it might vary considerably from site to site. One thing I think might have been lousy is the sanitation in bar serving. I caught two colds and one flu that I think was tied to Olive Garden.