Against established procedure, a manager at a site investigates an IT solution without involving the IT department. That's an internal problem. But the vendor selling the product calls us and starts requesting changes to our network. Without getting technical, I have a huge problem with this. And so inform the vendor:
"I don't know why you have a problem with this. I've done this at hundreds of companies much larger than yours and they didn't have a problem with it."
You want to guarantee my foot meets your ass? Imply that the way I do things in managing our IT infrastructure is the wrong way.