I use a STC-9200 in low pro situations and agree with Chris about the volume knob, it's not easy to move. In fact I would say it would probably be easier to move if it was in a bag with other gear that might be jostled around a bit. In the low pro situations, there are input and outputs on either side of the knob "protecting" it from being moved, so IMO a bigger concern would be cables pulling out of their place. I've actually had that happen but I don't think I've ever accidentally turned the volume off or down.
My setup is CA-14s/Cards > STC-9200 > DR-2d(line in), sometimes with CA-14s > UBB > DR2d(mic in). I have the STC-9200 set to +15 db and have never had an issue with overloading at those settings. I think the CA-14s > STC-9200 +15 db > DR-2D line always peaks around -8db for the loudest shows (metal) I attend. In fact sometimes I have to amplify by 12 to 15 db in post. I'm wondering - would +30db on the STC-9200 be too much? I've recorded with the STC-9200 set to +30db but it seems risky. The only time I've used the +45db setting was for bluegrass outdoors, it seemed even +30 would result in low levels.