The shirt will work, but I have an even easier solution. Wear a knit hat and a hooded sweatshirt. Put the hood up and clip the mics to the bottom of the knit hat near your ears. If you don't want to do this there's numerous other possibilities. Something that will work in this situation though is to take a knit hat and make a small hole on either side near your ears and just pop the mics out there and clip them. If it's a black hat especially nobody will notice the mics. The security are usually not even looking for tapers and definately not taking a long look at everyone in the show.
If you're taping in an arena though, you may not want to run FOB. If you're that far back from the stage, board usually near the rear of the hall, there is going to be much much much more reverb than you're going to want on your recording. Try to postion yourself at about the spot where the sound from either side of the stage should intersect in the audience, this will be the sweet spot. Anywhere else in a massive arena setting it's more than likely going to be a distant sounding recording. If you do choose to run FOB, stand about 10 feet in front of the desk. Also make sure your levels are not set too high on the MD to avoid any clipping. As for the stereo effect, the binaural mics are supposed to replicate the sound that your ears would have heard so having them as far apart as your ears will have the same result as your glasses. Shirt collar would be the same also. It's the spacing of the mics that provide the binaural effect. Any other questions I'll try to answer them.