The hardest thing in the world is not to strike or move your fly when you see a large steelhead on the surface going for your fly. Too many of us, including yours truly, have instinctly saved the fly by jerking it out the way on the encoming steelhead!
Two of the funniest things happened on one fishing trip in May to the Yuba River. I have a new Spey Rod and I was dragging the fly on top of the water setting the double D power cast. Just as I started to lift the fly up for the actual power cast, a 23-24 inch rainbow/steelhead (we never know what they are on our rivers) struck the fly. I ended up with about 60' of fly line all over me, my rod and the water in front of me. Fortunately the fish was stunned and just layed in the water as I recovered from my shock and got the line off of me and my rod and back on the spool. I was able to release him and get him recovered.
About 30 minutes later I had cast out about 65'. As the end of the fly line hits the water with a Spey cast, the terminal gear kinda floats up in the air and the fly settles slowly on the water. An even bigger fish jumped out of the water and struck the fly in air. He had 30' more line out on me before I realized what was happening. As my spool headed into the backing he got off due to currents and line slack!
A guide was behind me with 3 clients, and they were as amazed as I was. The guide wanted to know what time of cast that was. My answer, just good old unplanned luck!
Having said that, 98% of our steelhead are caught under an indicator or "blind" drifts. We never see the fish until after it is hooked and jumps to throw the hook!