Upload & Sell: Off
Totally depends on your business model.
Wedding photographers probably process most of their images before viewing/delivery. The customer is paying for that service.
Most of my business is youth sports, where 0% of the images are PP'd before client viewing. We shoot to sell, so what the sensor sees is what the customer sees.
We have some events where we sell after taking photos: if they buy prints, we'll touch (crop, possibly color correct and NR) every one of those before printing.
But about 40% of the photos are bought in digital format where they get what the camera got, burned straight to disc and delivered.
Other events, we burn everything straight to disc: 350,000 pix in 3 days went home with 12,000 competitors and coaches from 50 different countries at our last major event.... all straight from the camera.