One of the truly interesting things about the Don Valley trail is that it is one of the few places in the city of Toronto where people don't follow the rules.
The East Don Trail was built in part because people were already using the area when they weren't supposed to be.
During the multi-year closure of the trail around Riverdale in the 2010s, people were entering prohibited worksites so much that signs were eventually posted saying the police were monitoring. Everybody was like "yeah, obviously not" and just kept on trucking.
All to say: this fence, while attractive and well-built, will probably be intact for about five minutes before permanently having a broken section.