Probable cause and ad hoc roadblocks / stops

[Motor1]

JHB metro cops just seem to pull over and park then stop road users willy nilly.  They don't wear reflective clothing and don't display anything that demarcates a road block as such.

Is this a legal stop and is one obliged to show any form of ID on request?  If one is not breaking a law, what is the probable cause for the stop?  Sometimes SAPS do the same thing.

What do the legal eagles say?

 

[TheBear]

 

[Tommy Transalp]

 

[TheBear]

 

[Tommy Transalp]

 

[blauth]

 

[TheBear]

 

[Motor1]

 

[TheBear]

 

[Howie-WP]

 

[LeonDude]

 

[TheBear]

 

[Bundu]

 

[XTFREAK]

 

[Bundu]

 

[Motor1]

 

[Airguitar]

 

[Dwerg]

 

[2StrokeDan]

 

[IDR]