Well, out of curiosity I went and dug up the yearly Mariners-A's data from Retrosheet. I'm sure there was an easier way to get this information, but in case you're curious:
Mariners vs. Athletics, 1977-2006
G W L PCT RS RA
Total 405 163 242 .402 1687 1987
Home 199 94 105 .472 905 1001
Away 206 69 137 .335 782 986
Full year-by-year data here.
In short: Yes, the A's own us. But even more telling is how the Mariners have pretty much always been abysmal in Oakland. Even the 2001 Mariners team, which lost like 10 games all year, still only was .500 in Oakland.
But yeah, 69-137 isn't quite 80-200, but it might as well be. We're 6-19 at the Coliseum in the last three years, which would actually project to only 63 wins by the time we lost 200 if we kept losing at this rate.
We have 9 more games left against Oakland this year.
6 of them are at home.
Not pending rainouts, injuries, or acts of God, Joe Blanton should get two more starts against us.