So what. I don't care what people think about me using my MacBook Pro at Starbucks or at my gym or wherever. Let them laugh. I don't feel bad at all. A guy I used to work with laughed at all the rest of us for using our MBPs. He's now looking for work after going through 3 jobs in less than 6 months. He'd make fun of us but he was the one with all the network issues and problems.
Off-topic but why would you have a laptop at the gym?