Denied. One thing to remember is that software for this task has improved dramatically.
Another point is that the green signal is mostly contained within the luma sampling of the format, which is actually quite high.
Now, it may not be as advisable to actually pull the key in HDV. Less compressed intermediate HD codecs can often yield better results.
I have personal experience pulling a key from XLH1 24F HDV footage that was converted to DVCPRO HD, and was later intercut into an F900 feature. The material was a simulated blood splatter shot that contained tiny red blood droplets against a crappy green backdrop. All done with the basic FCP keyer in DVCPRO HD, no less.
This, of course, is to say nothing of the possibilites of capturing the uncompressed analog output for this purpose.