Srila Prabhupada explains in Caitanya Caritamrta that one may even accept diksa through authorized disciplic succession, but still it can be found that he will preach Mayavada philosophy. So it is not the diksa itself which establishes real connection to the sampradaya, it is siksa, or strict following of the instructions. Although both siksa and diksa are required for one to be connected to the authorized sampradaya, still the primary connection is through siksa.
Riga (date unknown)