Would you use a Canon G1X on the job?
I don't have a G1X- I wish I did...
but I use a G12 for theatre photography where the swivel screen, no shutter noise, face detection and great auto WB make life much easier than a DSLR sometimes. (Obviously the ridiculous high ISO on a D800 would have it's own advantages but I suspect a G1x would compete.)
The images from the G12 would never need to go bigger than A4 in the theatre's usage anyway.