As owner of Black Diamond GC, I will stick in my 2 cents worth which I have expressed before.
First, every WGT player is a free agent and if they leave my club for what they think is greener pastures, no hard feelings. Generally, except for reasons below, they are wrong and 1/3 have come back. There are some good reasons. Some want Skype clubs; some leave for predominately TC/C/TL clubs (we cater to all tiers); some want clubs that have more mobile players. I had one of our top players leave for a predominately Italian club; he had to use Google translator because he spoke virtually no English. Some want different kinds of club tournaments.
Second, no active club owner should be recruiting from other clubs. I have had batch invites to send to my club members by specific owners (who I won't name since I don't want this deleted.) The practice is despicable. Fortunately 98% declined, so I guess BD is doing a decent job.
Third, while I will never approach a member of another club, if they ask to join, I will accept them.
Fourth, if a club has an inactive owner, or is generally inactive with 5-10 active players, I might ease up on #2. But even then, if owner is active, I will approach the owner first.
But those who try raid active clubs, including their former clubs, are scum. The only exception I make to this, and I've run across it a few times (not BD but players I know), is if an active player gets ejected from a club because of dispute with owner, I will concede his right to contact his buddies in former club.