If skateboard deterrents refers to the nubs which are put on the railings for stairs, I'd say those come with more an ethos of, "This object is for the public t

If skateboard deterrents refers to the nubs which are put on the railings for stairs, I'd say those come with more an ethos of, "This object is for the public to walk up stairs more safely. You will not use it as a ramp-bar. That both makes it unusable for anyone while you are doing that and also causes it to break down from friction more quickly." Since there isn't really a fundamental human need to slide a skateboard down a handrail, I don't think it really counts as "hostile". It just represents, "I've agreed to provide a certain level of maintenance for this public handrail. Not enough to handle repeated skateboard friction."