Amsterdam does its own interesting take on both hostile design, as well as a few instances of “private” spike arrays positioned over gates, around drainpipes, and along other permeable borders dividing public and private spaces.

The thin line in your context between preventing public entry into private space, and discouraging public use of public space is worth examining more closely. The placement of design elements raises the question of where “public” stops and “private” begins, and the difference in tolerated behaviors between these two modes.

What barriers exist between public and private space where you are, and what behaviors are they discouraging?