I've never done the above with an audience performance for the reason I mentioned, but I've thought that given the right scenario, it might be possible to do something even more radical by turning the blumlein array 90 deg, placing it at the center of the stage and having the players on either side of it, with the audience now in the side '^' of the pattern and the empty backstage wall in the other side 'V'. Using the ensemble shape analogy, the players would form a wide 'U' with a hole at the bottom and the mic at the center. Say you've set up the mics so that the front 'V' of the blumlien array faces audience left (stage right). That means the audience is completely off to the left of the mic array, but since that quadrant is one of the ambient out of phase sections, they will be heard to both sides on playback, without sharp imaging and perhaps sounding somewhat 'out side the speakers'. The players in the back, at bottom shoulders of the 'U' would be closer to the mics than those at the top near the audience, so you would hopefully arrange them with that in mind and because one side of the ensemble will be flipped L-R in the playback image another really interesting thing should happen. Even though both 'close' players would be near the right limit of the mic array's pickup angle (remember, the mic array is facing to the left), on playback one will be heard at speaker L and the other at speaker R. Likewise the farthest players that are at the tips of the 'U' will also appear near the speakers but farther back, the players in the center of the 'U' uprights will image in the center of the stereo illusion.
Accurate in an absolute sense, certainly not. But it could provide a really cool playback illusion with tons of depth, sharp imaging of the players, diffuse imaging ambient sounding audience and rear stage wall reflections, and would get the mics even further from the audience, improving the always difficult musician/audience pickup ratio for a stereo recording.
I'd love to try that someday..