VT1
I sometimes have the honour to fly with an ex member of the ROC. He spent many years training to spot other aircraft and he is vastly better at it than me. I have always seen this as a challenge. If he is so good, then I can get better. See and avoid can and does work but you have to work at it and it is not perfect. The biggest problem with it is that most old spam cans have so many blind spots that it is hard to keep a good lookout.
Rod1