This spring a crabro queen was flying around my window looking for a place to nest. I wondered what would happen if I let her in, and next thing I know she starts flying around my room looking for a nesting location.
She chose this maculata nest hanging on my wall. For several minutes she was chewing up the inside layers of paper until about an hour later she flew back to my window, so I let her back out. Minutes later, she returned to my window, with a ball of wood pulp! She began constructing a nest inside the maculata nest, with me standing right there. I knew that having crabro nest on my wall isn't going to work out, so I moved the nest outside, but she just flew back to my window.
So to make a long story short I caught her and brought her several miles away so she wouldn't return.