After studying and discussing a bit, we have come to the conclusion that its not worth the risk of knee injury to be teaching Lotus pose. If any student can naturally do lotus, then their body does not need it. If any student cannot do it naturally, it is a risk for knee injury, and since there are many good alternatives, its not worth the risk.
One alternative is firelog. Another is half lotus. Here are some pictures to use in a practice for hip openers, and the video shows some nice variations to firelog. We do not recommend doing the lotus pose as the man in the video suggests.
