Auto SR is used by a number of receivers, in particular the embedded Seca units from Pioneer
Most simply rotate between the five different symbol rates in a way that you do not recognise, only the locking indicator lights up slightly later - ala the Hyundi Irdeto machines
Blind search is also a now thing, (Pioneer again) and in some respects the Digiquest P2000 and Simba receivers - from Aston in France - have always had such a system
Blind searches if performed correctly will take a full night to achieve