That’s not how it rolls. The online giant has temporarily suspended sales of some of this year’s trendiest gifts: self-balancing two-wheeled scooters. Manufacturer Swagway says Amazon is seeking assurances that the devices meet specific battery and charger safety standards following several reported fires linked to the so-called hoverboards. A number of airlines have also banned them as a precaution. Sales by smaller competitors may be harder to regulate, but Swagway and other big players are taking the wheel to put safety first.