> Also in urban environments, making a lot of "inviting" public spaces for people to hang around and loiter is not always a great idea.. this also attracts a lot of crime, drugs etc

This not problem for inviting spaces per se. But spaces where you can hide. If you have this in ordinary "inviting" public spaces the that is sign of dysfunctional society. Most parks and town squares in cities I have lived are safe (at least if you are man).