My wing has the same policy. As a CI who had come to the wing from another (with several years break in between being a cadet & staff), when I went in to uniform I had extreme pressure put (read for that almost forced) upon me to transfer.
I argued successfully against it (as did my CO). My reason being that my Sqn at the time were struggling for staff & taking me away would make absolutely no sense because every other Sqn around me was better staffed. My Sqn would lose out just because of a blanket policy that did not apply in my case.
For a cadet who has aged out & wants to come back as staff, I believe it should be 'encouraged'. I disagree staff should be moved (like my example) just because.
But it should be done where practicable. If it won't work due to distance, or because it would leave one Sqn under strength, then it should not be done.