I can imagine an engineering team turning to Interaction Design as part of their work turning Product Owner stories/use cases into product. (Ok, I don’t need to imagine this, but I’m going to assume I’m not unique here…)
I can imagine that as you get into the conversations that are part of IxD the Product Owners might feel threatened, because suddenly engineering is asking penetrating questions about who these users really are and what they’re really trying to accomplish. A PO who’s used to getting away with vague descriptions might take this personally, might interpret this either as an attack or as a power grab by engineering. (Ok, I admit that I’m not just imagining this.)
I think engineering is less likely to respond this way to the PO bringing IxD into the process since these questions/issues fall more naturally into the PO domain and less into the engineering domain. The exception are the UI people who might feel like IxD infringes on the creative aspect of their jobs.