Kids being kids (and sometimes adults being adults!), tablets can get dropped or knocked. Given that tablet screens are basically glass, there is always a possibility that the tablet could get damaged. Eliminating this problem completely isn’t really possible, but there are measures that can be taken to reduce the chance of serious damage to the tablet.
The nabi 2S comes with a protective red bumper. This protects the sides of the tablet, with increased protection at the corners, which is where glass is at its most vulnerable, and cut-outs for the different ports and cameras. This doesn’t eliminate the chance of damage, but it does greatly reduce it. Screen protectors and carrying cases can also be purchased which also help reduce the chance of damage, including scratches to the screen and adding further protection against bumps and drops.