Really?? How sad. Way to alienate your alums.
Once a sister, always a sister!
When my chapter's alumnae relationship person does her job properly (some are better than others), she keeps us alums informed by email (and sometimes, snail mail) about the dates for rush and initiation. I've never made the trip myself, but we're always welcome.
Edit: The place where my chapter holds initiation has plenty of room, so space isn't an issue. I can understand where a chapter would not explicitly invite alums if space is tight. But I can't imagine a chapter deliberately turning alums away. It's so rare to find alums who have remained involved - why alienate them?