Manufacturers have said there is a risk. It’s always tempting to dismiss "pass it on" rumors as bunk, but the fact is that mobile phone manufacturers have warned consumers in the past against using the devices near gas pumps for a reverse lookup phone number. Similarly, the shielding in passengers’ devices also degrades due to the passage of time and, in some cases, repair procedures. The kernel is maintained by Linux leader Linus Torvalds and his allies, who have preferred to work on mainstream enhancements rather than on features geared specifically to "embedded" computing devices such as cell phones, robot controllers and automated teller machines. An array of academic, social, safety and wellness, transportation, utility and administrative services are delivered to students with these devices.