> Even if manspreading would be an issue, which it is my belief that it is absolutely not, ...

This leads me to believe that you haven't actually see it in action, and I wonder how much you travel on public transport. Absolutely it is a problem - I can't tell you how often my physical space has been unnecessarily "spread into" by this sort of thing.

> ... it would affect men more than women since men are generally speaking physically larger than women.

My observation is that men simply don't "manspread" into another man's space. It's very much a dominance thing. It's ugly, it's obnoxious, and it's borderline threatening.

I have no faith that this initiative will have any effect, but it most definitely is an issue.