Tower PCs are not like Dumbbells. Dumbbells are designed for working out certain muscles for a short period of time. Tower PCs are awkward to carry, and are often really heavy. I could see how carrying a Tower PC up stairs or long distances could injure someone. People do carry their Tower PC to LANs, or to a friends out etc. Someone could add wheels, and mount a handle to the shell of the case to move it around easier. Or just disassemble, and reassemble the PC.