I'm glad they keep banding here, too, but sometimes I feel really selfish about it. I love learning a little more about the birds' private lives (at least that they stick around from winter to winter, they seem to stick with the same 'crowd' and most importantly, they're surviving! But I worry that some might be hurt in the net or so stressed by the banding that they become sick. I haven't seen any untoward signs of illness or found any dead ones, but still, that thought hangs there in the back of my mind.
If I ever saw evidence of injury, I think I'd close it down...