Hi,
I've translated a section of a report from 1937 which describes the role of the HJ-Streifendienst (SRD) at that time:
The SRD monitors all Hitler Youth members in accordance with the provisions of the 1936 State Youth Law. The following are monitored:
General bearing and conduct of HJ and BDM personnel
The correct wearing of uniforms
Visits to public houses and bars
Order and cleanliness in youth hostels
Hiking trips
Additional responsibilities and duties of the SRD within the Hitler Youth are:
Security and order at large rallies/events
Policing of tented summer camps
Escorting of vehicles/convoys
Missing person investigation
Conducting investigation/enquiries into criminal acts and failures to comply with HJ regulations
Offering advice and assistance to hiking groups
Railway security
The protection of the youth from criminal elements
Combating youth crime
Prevention of damage to public property by travelling youth formations
From 1939 the SRD gained new responsibilities and its work became increasingly difficult but in essence the SRD was the HJ movement's internal police force* albeit a force with no judicial powers. It worked closely with the German police and there was certainly work done by the SRD to infiltrate illegal youth groups but a Gestapo they were not. Certainly nothing I've read would lend any weight to that comparison anyway.
I think it definitely possible, as you say, that the SRD were very probably keener than most to spot and report signs of treason and defeatism among the population but I have no specific information on that. What have you read in this regard?
*not a 'patrol service' as is often stated in modern English language reference books
Big subject and a very good area to discuss