Actually, the nastiest biker I knew owned the chopper shop. But to your point, the crowd the suspect hung around would be pertinent. The defense doesn't need to be asking the store owner if he hung around the wrong crowd. That would be the investigator's job when trying to find a perpetrator.
Actually, I was thinking of a case locally, where because the owner belonged to such-and-such a club he was broken into. I think in this van Dam case, wityh the high likelyhood of a sexual motive for the potential crime, that the sexual life of the parents is pertinant and necessary, not only in investigation and grand jury, but also in defense during trial.