[twitter-dev] Re: Revoked Access

[jaronbarends]

And as an addition to what D. Smith said: you're probably storing your
users' token and token_secret somewhere. So if you do have a tokens
are present, you know they have granted access before. Also, you can
check the message in the headers. Twitter sends a 401 when access has
been revoked, and last time I checked, the accompanying message was
"Could not authenticate with OAuth." However, these error messages are
not set in stone, and afaik they are not officially documented by
Twitter.