Looks like some sort of weird cinder block. Unfortunately, that makes a simple shelf a harder thing to hang as you'll need to use masonry anchors. They tend to be bigger and harder to hide. To control the bounce, go slow and start with a smaller diameter bit.

They're getting smarter too though so if geo-fencing alerts are built in, parents may get notified. But yes, ebikes/scooter's may provide some additional assistance in the sneaking as well.