I can pretty much confirm this is the case. I was told as much way back in 1996 at a job interview for the local part of (the what was then unnamed but now has

I can pretty much confirm this is the case. I was told as much way back in 1996 at a job interview for the local part of (the what was then unnamed but now has probably changed its name again) Echelon network. (Run out of the GCSB in NZ). That is, it was explained to me that while we don't 'spy' on our citizens we supply as part of the partnership the ability for each member country to basically circumvent those restrictions because the entity doing the surveillance is actually a foreign government (all be it an ally). Not exactly in those terms but I was left in no doubt that that was how it worked. Of course if they told me that a job interview I imagine it was regarded as public knowledge.