If the basement people ever need to make some potentially-catastrophic decisions (for which a misprediction is catastrophic), then the manipulators can wait until those decisions to break the predictor. Waiting is probably cheaper for the manipulators than gathering more data is for us (or at best they are proportionally expensive, so doesn’t change the calculus at all).
If you are in something like the low-stakes setting, then there’s no opportunity for a manipulator to do too much damage—every time they do some harm they lose a bit of probability, and so there’s a reasonable bound on the total harm they can do.
If the basement people ever need to make some potentially-catastrophic decisions (for which a misprediction is catastrophic), then the manipulators can wait until those decisions to break the predictor. Waiting is probably cheaper for the manipulators than gathering more data is for us (or at best they are proportionally expensive, so doesn’t change the calculus at all).
If you are in something like the low-stakes setting, then there’s no opportunity for a manipulator to do too much damage—every time they do some harm they lose a bit of probability, and so there’s a reasonable bound on the total harm they can do.