As a Stroud's customer of many years, and also as someone who has worked in the restaurant business for 40 years, I can say with relative confidence they didn't "forget" the seasoning on your one order of chicken.
I'm not saying they didn't mess up. I'm just saying that any place that does fried chicken in the kind of quantities Stroud's does, isn't individually seasoning each piece of bird. They'll premix their flour/seasoning in bulk and in the proscribed proportions at the beginning of the night (or even have large quantities of a pre-made mix, prepared to their specs by a seasoning packer) and use that to prepare the chicken, thus insuring uniformity. Therefore, if they screwed up your order, they screwed up EVERYBODY'S order that night. And if that happened, knowing the way Stroud's operates, they would have discovered the error long before you were served.
Again, I'm not saying you're wrong--you tasted what you tasted and no one can argue with that. Furthermore, The Travelin Man has said he's had a similar, unconnected experience.
I would argue though that the issue you're talking about is, exactly as stated above, a matter of taste. You might just not care for the type of chicken Stroud's serves. I can tell you definitively, that in roughly 50 visits to Stroud's, over the years, I've never had any problem with the flavor (or lack thereof) in their product. It has never tasted bland or under-seasoned to me. My wife will testify, under oath, that I'm not shy about my salt/seasoning intake, and I've never had to add salt or pepper, or any other kind of seasoning to a meal from Stroud's.
Again, not saying you're wrong, just saying, maybe, Stroud's chicken doesn't fit your personal Fried Chicken Flavor Profile.
Hope the rest of your stay in KC provided better food experiences.