MasterGadgeteer, annoyed? No. Amused? yes.

As for the knee, you are fortunate it is not causing too many problems. I had my meniscus scoped enough times that I don't have any in my right knee. That lead to my partial knee replacement because bone on bone is painful. Now I have artificial cartilage that will outlast me. My Mayo ortho doc told me that getting it scoped would lessen the pain, which it did. Go for it.

I would also consider wearing a compression knee sleave to help support & stabilize knee while portaging. You never know when you might slip...