Noel Borthwick [Cakewalk]
... placing a couple of field recorders and cameras and hope for the best...

That's a cool way of being non-intrusive.
 
On a side note, phase correction IMHO is terribly important and makes a huge difference. "Channel Tools" makes it really simple and the Sonar video about drum production explains it in detail but it would be great if we could simply read the length of a mouse selection on a clip in terms of samples rather than having to split as explained in the video ...
 
BTW, beware "Channel Tools" has a problem: on stereo channels with the link button engaged it does not change the sample rate for both sides ... so when adjusting you might not notice that you only changed one side of the stereo image (and in this way introduce something that sounds like panning but is actually a few samples time shift) ... on a drum kit recording you might notice that if your snare starts moving out of the center on your rooms mics (given that you placed mics for proper stereo image in the first place) ...
 
Another tip for making phase correction easier: instead of looking for a transients in the recorded material, have the drummer play single snare and kick hits and record them for determining differences in sound wave travel times (that would also work for live environment i.e. record a bit of the sound check to easy later phase correction)