Did ask for one several times in during my CFI time in the US, at the one (military) airfield we happened to be close to. Were told that we would be allowed to do so until a missed approach, but we wouldn't be allowed to touch. However the PAR controller was unavailable at that time, but we were invited back. However at that point in time I was flying with a PPL student... and so on. Never did get to do one =(
(We did ASR approaches on a regular basis though, most controllers were happy to get the practice)