yes done it. work when target is too locked for direct contact. current op i have family number as fallback - pacific northwest contacts. if target stonewall i go that route. but caller must be solid, no mistake on this play.
few reason. some target have good IT behind them and you dont know until you already in. some just have instinct and go cold for no clear reason. and sometime the payout is not worth the time invested. had one last year, CFO at midsize bank on east coast, three month of work and the account was frozen before i could move anything. you learn to qualify target early.