This would be very useful when we setup production kind of deployments and use it by many users. According to current architecture if logged out from one device and revoke key then all other call made with that token will get authentication failures. In that case application should be smart enough to detect authentication failure and request for new token. Once user log into application, that user might want to provide user name and password. So we can use that information and consumer/ secret keys to retrieve new token once detect authentication failure. In our honest opinion we should handle this from client application side. If we allowed users to have multiple tokens at the same time. And that will cause to security related issues and finally users will end up with thousands of tokens that user cannot maintain. Also this might be problem when it comes to usage metering and statistics.
So recommended solution for this issue is having one active user token at a given time. And make client application aware about error responses send by API Manager gateway. Also you should consider refresh token approach for this application. When you request user token you will get refresh token along with the token response so you can use that for refresh access token.
How this should work
Lets assume same user logged in form desktop and tablet. Client should provide user name and password both when they log into desktop and tablet apps. At that time we can generate token request with username, password and consumer key, secret pair. So we can keep this request in memory until user close or logout from application(we do not persist this data to anywhere then there is no security issue)
then when they logout from the desktop or the application on the desktop decides to refresh the OAuth Token first, then the user will be prompted for their username and password on the tablet since the tablet has a revoked or inactivated OAuth Token. But here we should not prompt username password as client is already provided them and we have token request in memory. Once we detect auth failure from tablet app it will immediately send token generation request and get new token. User will not aware about what happen underline.