Once again, the idea that anyone at all would be allowed to discuss what Islam demands of its followers in this kind of debate is defeatist. If someone shows up at your chess club with some exotic version of Chinese checkers they made up last week, the issue is not what the infinitely malleable rules of the invaders game are. It is that he is at your chess club cause he came to your chess club and no one made him. So play chess, or go home. The only rules to be debated, are the rules of chess. How much more clear can you get than that? Whether or not burkas or prayers are mandated by Islam means exactly nothing and must must must continue to mean nothing. Religious freedom means free from government persecution for calling your god by another name or worshipping another god.
It was never meant to mean that anyone can do anything if they claim their religion mandates it.
Play chess, or go home.