well, no strong opinion about private vs permissive tags here neither.

I happen to pass by there quite often, but mostly on week ends and, most of the time, the gates near Av. de Bouchout are closed. This is why it didn't surprised me that a fellow mapper marked the roads as private. I did the same for the sidewalks for the shake of coherence.

A few years ago, those gates used to be wide open but, these days, the whole 'Plateau du Heysel' has become a place where urban rodeos take place almost every single night. I guess this is the main reason why those gates remain closed as much as possible.

I changed the access tag of the eastern sidewalk, which allow to access the archery range next to it, to permissive as well: https://www.openstreetmap.org/changeset/164179051

Cheers