Earlier quoted context omitted.
As good as your past intentions sound, if somebody I didn't know from another department just came and sat next to me to watch me work, without me knowing it would happen beforehand, I'd put in a complaint too.
Your behavior in that case will be less than ideal. It will be better to talk to your reportee and the individual and understand what's going on if you weren't in the loop. This could have easily been the birth of a strong partnership between sales and the dev team to understand how people both really use and demo the product. Assume positive intent. This business of putting in complaints behind someone's back (bear…
By the way the employee didnt complain. They were happy to have someone fixing their companies app. The sales manager was watching from afar with dissent. Plus I tried asking the programming manager about the app first, so he could follow company hierarchy. He was too busy playing video games on his PC & just shrugged his shoulders. My choices were basically slack off like him, snitch on him to the CEO, or go get the answer elsewhere. The latter seemed most appropriate.