Actually it's a legitimate concern. If Green proxies his 7% to the RST then he would dwarf the current percentage held and controlled by both the members who hold community shares and those members and non-members who have proxied as it stands.
However the proxy rules quite categorically state that in casting our collective vote the Chair must reflect, in the first instance, the views of the members and, in the second instance, the view of the wider support. The rationale behind this aspect of the rules is that the RST is a one member, one vote organisation and neither size nor financial clout can outweigh the democratic majority.