William Porter , Oct 19, 2009; 03:58 p.m.
"please dont tell me it's because of low-light situations...."
Hmmm. So what answer ARE you looking for?
There is definitely nothing magic about 1/60th sec. But my work inside the church does produce a lot of photographs at speeds somewhere between 1/30th sec and 1/100th sec. 1/60th sec might indeed be an average or close to.
I don't usually use a tripod in the church (except for the formals, and then I'm using flash). I shoot Pentax so I have a couple image-stabilized bodies with me. (Nikon and Canon shooters may be using image-stabilized lenses.) A wedding ceremony isn't (usually) an athletic event, and the subjects tend to be pretty still, so I CAN shoot at 1/60th sec and hope to get photos that are sharp or sharp enough. A tripod won't help me much because if I get slower than about 1/30th sec, subject movement becomes a bigger risk than camera shake and neither image-stabilization nor a tripod can do anything about that. In other words, I can get to 1/60th sec or 1/30th sec hand-held - and that's about as slow as I would dare to go even if the camera were mounted in steel.
Now, the ONLY reason that I do this is that the light in just about every church I've shot in is pretty subdued. I push my ISO up pretty high - shots in the church are typically between 800 and 1600. And I open my lenses up wide: I'm typically shooting at f/2.8 or, when possible, faster than that. But if I'm shooting at 1/60th sec it's because, even after pushing the ISO up high and opening up wide, I STILL need to slow down the shutter to get a decent shot. And even then, I simply count on the shots inside the church having a certain degree of noise.
I think there's nothing more mysterious to it than that - and I suspect everybody else's answer will be pretty similar.