Supervise younger children.
Please be mindful that a degree of balance and a common sense approach to foot placement is required for safe use of the step stool, this is something that a younger child may not possess or understand.
In the fig's below is one example of how a child (or anyone for that matter) could have a mishap while climbing the step stool. Also shown is how a side extension piece may help minimize such a mishap.
A young child climbs up the step stool placing his/her foot near the front of the top step.
The young child continues to climb with his/her foot near the front of the top step.
A slight pushing away movement causes the step stool to tilt over and the child to fall off the stool.
A side extension piece may help minimize a possible 'fold-back' mishap.
Even with the side extension, the same rule still applies -" the step stool is not recommended for younger children" - although the extension will add a bit more stability.
Adding at least a 50mm (2") wide extension to the sides of the step stool will add more stability.
Note 1: The wider the extension, the less chance of a fold-back mishap.
Note 2: The photo on the right is to show how a child is likely to place his/her foot near the front of the top step rather than in the middle, setting up for a possible mishap as the climbing continues.
The side extension piece may help minimize the chance of a 'fold-back' mishap.