No, it is not for leapfrogging over or sitting on, there's a real reason and Cathy Pedrayes from TikTok explains below!
It turns out, they're concrete bollards!
Which is a fancy way of saying they're concrete structures that are placed on the sidewalks in front of the stores to stop vehicles from driving into the building.
Now, they've just become synonymous with the Target brand.
Think about that the next time you go on a Target run!