"We want to launch a product in category X"
"Ok, should we roll it ourselves, or buy something?"
"Well, let's interview a few companies, see if there's any we like, and if not, we'll make it ourselves"
A) copy; B) buy; C) sue
you're always violating some patents by IBM and the like, sometimes they don't want to compete with a product only to get you off the table... and sometimes they can do that easily
Oh, and there is the enterprise variation (option D?): talk with the costumers and demand that they stop working with the competition