I'm not a big fan of Hanon or anything else like that for a warm up, but I definitely feel I play better to start with if I've played for a few minutes on the piano before I go to the gig, and if it is more than a regular gig (something for the industry people or such), a little warming up doesn't hurt!
But usually, it's more just a piece or two, sometimes some classical, sometimes a pop tune, sometimes just a passage that gives me a challenge. And, honestly, it's not really done as a warm-up... I just love playing! At least I have an excuse for it in the morning
In the studio, though, it's essential... If something magic happens on that first take, you don't want to lose it by running out of steam or stupid simple fingering errors!
But the thought of NOT warming up because we are 'working professionals' and gig two or three times a day? Tell that to any professional classical pianist, the guys with possibly the most technically demanding gig out there... you won't see THEM playing a concert without a warm-up very often!