The second paragraph[1] of "202 Accepted" is a poor fit for
PaceServiceError.
Note that there is nothing meaningful to return in the
message body.
This violates a SHOULD-level recommendation.
It seems like 202 is for "process that terabyte of experimental data" or something like that.
I want to return to section 9.1.1 of the HTTP spec[2]:
[...] If this is not a valid use case for this section of the spec, what would be?
Is this paragraph utter nonsense? This would seem to indicate that GETs need not be side-effect free, only that the user has committed to nothing by sending the request. By sending a request to the ErrorURI, what has the user committed to that exceeds a normal GET request?
There's no requirement that the server ever change the URI, though doing so would certainly be useful. Keeping previous URIs dead is implied by the 410 status code.