Well, let's hope so.You guys spend way too much time worrying about, and practicing stuff, that will never happen to you.
Talk about never happening, in my (iantd) class, training for open water tech, I had to remove my mask, spit out my reg and swim 50 feet blind to the donor (I swear it was more than 50 feet) and share gas. What is this? In case I loose my buddy, lose my mask and run out of gas, but manage to find the buddy in a desperate vertical swim?
Okay, I admit, it was fun to do. And I enjoy the eyes-closed ascent. There is a real zen-like state I get into when I'm totally in the dark, the most relaxed I feel underwater.
I once did use my backup mask when a buddy broke his strap and I had to give him my backup.