Actually, I don't think that pollination in the boot is always how it works. In my experience with 27 species of exotic annual grasses I've noted that cleistogamy appears to operate primarily in times of drought stress when the plant is producing seed late in the season of a Mediterranean climate and might not even make it all the way out of the boot. Seed appearing earlier in the season seems to erupt so quickly that it could well be infertile upon emergence and available to open pollination as I see anthers on the spikelets. In a climate like Oregon which has a longer wet season than a place with snow melt it is more likely that this phenomenon might occur.
Now, I'm not so much of a grass geek that I know this for a fact, but my guess is it's probably legit. If you need more than that, I'd probably have to defer to an acquaintance of mine at UC Davis. I could make a few phone calls on Monday and ask him if I have it right.