I go to the cinema quite often and I wouldn't appreciate listening to the Lord's Prayer, not that I object to it myself, I don't, if anything it makes me feel nostalgic because reciting it was very much part of my childhood.
I take the view that a wide range of people go to the cinema, some will be religious, some will be atheists, some will be agnostic. Having the most renowned Christian prayer recited at random audiences would open the floodgates for other religions to want a similar opportunity and I think that will open a can of worms. Out of deference to those that are not Christian, atheist or whatever I think a place such as the cinema should remain secular.