It's not clear whether this works. On the one hand it does keep the homeless visible. On the other hand it also punishes people who can't practically participate in local politics (tourists for example). And in general, politically powerful people aren't waiting at bus stops all that much, so this strategy doesn't seem all that well-targetted.
It may also be counterproductive in that it makes people less rather than more willing to support measures that help the homeless and instead promote measures that punish them in return. That is, punishment may encourage more punishment in response.
But I'm just speculating here. It seems like this is unlikely to be settled without actual evidence.