Jason, you make it sounds a bit like becoming a Chartered Engineer. Fill in the form, get a couple of people to say nice things about you, pass an interview and then pay the excessive fees every year to add four letters after your name. Back in the 1980's anyone joining the BCS was immediately made a CEng they were so desperate for members.
Shame such memberships are not as widely recognised as having any real meaning, unlike in Academia where you are given an internationally recognised title, for life 
(I note that the IET have no problem asking me to provide presentations at their professional events even though I choose not to fund their institution as a member.)
Jo