All the airports that have a 1000' TPA
are "non-standard," although the rule of thumb you have written has
become it's own standard of sorts. This is why I brought it up. If
you're flying in a Piper at 1000' thinking it is correct, and I'm
flying a Cessna at 800' which is what was published, we're going to
have a problem because we won't be able to see each other if we're in
close proximity.
[...]
I believe when a TPA is not explicitly stated
in the AF/D the expected TPA is 800' AGL.


The hazard indicated is real, but the altitudes are no longer correct.
According to my AIM (2000, 4-3-3) a pattern of 1000 feet is reccomended unless
established otherwise. However it seems that some airports have retained the
historical 800 foot altitude you indicate was once standard, but have not
ensured that the AF/D is apprised of this. Thus, us newfangled pilots (the
ones minted after VORs g,d) will enter at 1000 feet, only to be surprised by
folks 200 feet below us. (this was exactly what I found at GBR not too long
ago).

Jose

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