Presumably most or all of these services will let you rotate your secret key, and Instapaper will do that. Assuming it was done rather quickly, then there would

Presumably most or all of these services will let you rotate your secret key, and Instapaper will do that. Assuming it was done rather quickly, then there would be no practical risk of unwanted access for any of the OAuth accounts. If the services don't let you rotate your secret key, well... they probably should.