I always use my forearm and sleve of my shirt to wipe sweat off my head when exercising. I don't even think to get a towel sometimes. It's just more convenient.
When exercising at the gym I have my valuables with me but I always try to keep them concealed, which means I put them under towels, tucked in my sweatshirt, or under other gym equipment.
Whatever augmented exercise equipment our team ends up making, it will have to be something that fits with the rest of the gym equipment and doesn't seem like it is worth stealing.