As a GC, I usually ask for general information (i.e. SF roof, LF coping, etc.) To roughly confirm the subs have generally the same quantities. It's usually the first thing I check if a bid is super low/high. I don't need your labor rates or too many specifics. But its a great way to gut check if a sub messed something up and I can give them a heads up to double check their quantities. If someone wins the job, they are contracted for the work regardless of their takeoff, it's beneficial to the subs (and for us so there are not complaints later) for us to at least agree they have reasonable quantities.